Systems and methods for providing cooling to a heat load

ABSTRACT

Conditioning systems and methods for providing cooling to a heat load can include an evaporative cooler arranged in a scavenger plenum with a pre-cooler upstream and a recovery coil downstream of the evaporative cooler. Outdoor or scavenger air can be conditioned in the evaporative cooler such that the conditioned scavenger air can provide cooling to a cooling fluid circulating through the recovery coil. The reduced-temperature cooling fluid can provide liquid cooling or air cooling for an enclosed space (for example, a data center) or for one or more devices that are enclosed or open to the atmosphere. Given the design and arrangement of the pre-cooler, evaporative cooler and recovery coil in the plenum, the system can operate in multiple modes. The pre-cooler can be configured to circulate a cooling fluid to condition the scavenger air. The pre-cooler fluid circuit can be coupled or de-coupled from a process cooling fluid circuit.

CLAIM OF PRIORITY

This application claims the benefit of U.S. Provisional PatentApplication No. 62/382,176, filed on Aug. 31, 2016, the benefit ofpriority of which is claimed hereby, and which is incorporated byreference herein in its entirety.

This application is a continuation-in-part of International ApplicationNo. PCT/CA2016/050252, filed on Mar. 8, 2016, and a continuation-in-partof International Application No. PCT/CA2016/050507, filed on May 2,2016. International Application No. PCT/CA2016/050252 claims the benefitof priority of U.S. Provisional Patent Application No. 62/162,487, filedon May 15, 2015. International Application No. PCT/CA2016/050507 is acontinuation-in-part of International Application No. PCT/CA2016/050252,filed on Mar. 8, 2016, and claims the benefit of priority of U.S.Provisional Patent Application No. 62/162,487, filed on May 15, 2015,and the benefit of priority of PCT/CA2016/050252. Each of theabove-listed applications is hereby incorporated by reference herein inits entirety.

BACKGROUND

The present application relates to conditioning systems and methods forproviding cooling to a heat load. In an example, the heat load can befrom an enclosed space, for example, a data center, and cooling can beprovided by cooling the air or heat-generating components in theenclosed space with liquid or air cooling. In an example, the heat loadcan be from one or more devices or other piece of equipment that may ormay not be arranged within an enclosed space.

There are many applications where cooling is critical, such as, forexample, data centers. A data center usually consists of computers andassociated components working continuously (24 hours per day, 7 days perweek). The electrical components in a data center can produce a lot ofheat, which then needs to be removed from the space. Air-conditioningsystems in data centers can often consume more than 40% of the totalenergy.

With the current data centers' air-conditioning systems and techniquesand significant improvements in IT components operating conditions andprocessing capacity, servers can roughly operate at 50% of theircapacity. This capacity limitation is due, in part, to the coolingsystems not being able to cool the servers efficiently and the serversreach their high temperature limit before reaching their maximumprocessing capacity. High density data center cooling seeks to coolservers more effectively and increase the density of the data centers.Consequently, this will result in savings in data center operating costand will increase the data center overall capacity.

The high density data center cooling can be achieved by using liquidcooling technologies to reject the heat at the server. Data centerliquid cooling affects the data center energy consumption in two ways:(1) utilizing maximum server processing capacity and data centerprocessing density which will result in lower cooling power consumptionper kW of processing power in the data center, and (2) generallyliquid-cooling systems are more energy efficient than data centersair-cooling systems. The liquid cooling technology can capture up to100% of the heat at the server which can eliminate the need for datacenters air-cooling systems. The data center liquid cooling can save upto 90% in data centers cooling costs and up to 50% in data centersoperating costs. Also, data center liquid cooling can increase theservers processing density by up to 100%, which can result insignificant savings.

Overview

The present inventors recognize, among other things, an opportunity forimproved performance in providing cooling to a heat load using aconditioning system having an evaporative cooler in combination with anupstream pre-cooler and a downstream recovery coil. The heat load can befrom an enclosed space or from one or more devices. In an example, theconditioning system can produce cold water (or other type of coolingfluid) for providing liquid cooling or air cooling to the enclosedspace. In an example, the conditioning system can produce cold water (orother type of cooling fluid) for providing liquid cooling to a device orother piece of equipment not arranged within an enclosed space.

The three components of the conditioning system can be arranged inside ascavenger air plenum configured to receive an outdoor or scavenger airstream and direct the air stream through the plenum. The evaporativecooler can condition the outdoor air such that the conditioned air canpass through the recovery coil disposed downstream of the evaporativecooler and cool water circulating through the recovery coil. Thereduced-temperature water exiting the recovery coil can be used forliquid cooling or air cooling for the heat load. The pre-cooler can belocated upstream of the evaporative cooler and can be configured toselectively pre-condition the scavenger air depending on the outdoor airconditions. The reduced-temperature water or cold water can also bereferred to herein as process water or cold process water, since this isthe water produced by the conditioning system and used for providingliquid cooling or air cooling to the heat load.

The inclusion and arrangement of these three components (pre-cooler,evaporative cooler, and recovery coil) in the scavenger air plenumallows the conditioning system to operate in multiple modes depending inpart on the outdoor air conditions and an amount of cooling needed forthe heat load. In an economizer mode, the pre-cooler and the evaporativecooler can be bypassed since the outdoor air conditions are such thatthe scavenger air does not need to be conditioned or cooled prior to therecovery coil. In a normal or evaporation mode, the pre-cooler can bebypassed but the evaporative cooler can be used to condition thescavenger air prior to the recovery coil. In an enhanced mode, thepre-cooler can be used to pre-condition the scavenger air prior topassing the scavenger air through the evaporative cooler.

Examples according to the present application can include conditioningsystems for providing liquid or air cooling to a data center having ITcomponents.

Examples according to the present application can include conditioningsystems having any type of evaporative cooler configured to condition ascavenger air stream using an evaporative fluid. In some examples, theevaporative fluid in the evaporative cooler (for example, water) can becollected and used for providing liquid cooling or air cooling. In thoseexamples, the evaporative cooler can directly produce cold water forliquid cooling or air cooling, in combination with the recovery coil. Insome examples, the evaporative fluid in the evaporative cooler is notcollected, in which case the evaporative cooler indirectly produces coldwater by conditioning the scavenger air prior to passing the scavengerair through the recovery coil, and the recovery coil directly producesthe cold water for liquid cooling or air cooling.

Examples according to the present application can include conditioningsystems having an evaporative cooler that operates in an adiabatic modein which the evaporative fluid in the evaporative cooler recirculatesthrough the evaporate cooler in a closed fluid circuit confined to theevaporative cooler. In some cases, the evaporative cooler can switchback and forth from the adiabatic process to the configuration in whichthe evaporative fluid from the evaporative cooler can be collected foruse as the cold process water (or other fluid) for liquid cooling or aircooling.

Examples according to the present application can include variousdesigns of the cooling fluid circuit for the pre-cooler. In someexamples, the cooling fluid for the pre-cooler can be coupled with theprocess cooling fluid (i.e. the cold water produced in the recovery coiland, in some cases, the evaporative cooler) such that the pre-cooleruses the water flowing through the recovery coil or evaporative cooler.In other examples, the cooling fluid for the pre-cooler can be partiallydecoupled such that the fluid circuit through the pre-cooler can beseparate from the process fluid circuit through the recovery coil orevaporative cooler within the plenum, but the cooling fluid for thepre-cooler can be taken from a reservoir or main supply of cold waterproduced by the recovery coil or evaporative cooler. In yet otherexamples, the cooling fluid for the pre-cooler can be wholly decoupledsuch that the cooling fluid circuit for the pre-cooler can be separatefrom the process cooling circuit.

Examples according to the present application can include conditioningsystems having multiple cooling units with each cooling unit having theevaporative cooler and recovery coil, and optionally the pre-cooler. Thepre-cooler can be an optional component that can be included dependingon the climate where the conditioning system is to be installed. Byproviding a partially decoupled or wholly decoupled pre-cooler design,each cooling unit can have a standard cooling capacity independent ofwhether a pre-cooler is included and how much it operates.

Examples according to the present application can include aliquid-cooling system for a data center, the liquid cooling systemhaving a Liquid-to-Air Membrane Energy Exchanger (LAMEE) as anevaporative cooler, which can reduce the data center cooling energyconsumption compared to conventional air cooling data centerstechniques. The liquid cooling system can be significantly smaller insize and lighter compared to other direct evaporative coolers (DEC),including air-cooling DECs. The liquid-cooling system as describedherein can reduce the water consumption in comparison with otherevaporative cooling systems and can reduce the operating cost of thedata center. Data centers liquid cooling can be effective since atypical liquid, such as water, at the same volume flow rate as air, hasalmost 350 times higher thermal capacity than the air. The system caninclude a cooling fluid circuit connected to the cooling fluid flow pathof the LAMEE and recovery coil and extending from the plenum into thedata center. The cooling fluid circuit can be used to deliver reducedtemperature water from the LAMEE and recovery coil (or a reducedtemperature coolant) to the data center to provide cooling to the datacenter without moving air from the data center through the coolingsystem.

Examples according to the present application can include an air-coolingsystem for a data center or other enclosed space, the air-cooling systemhaving a LAMEE as an evaporative cooler. The LAMEE and the recovery coilcan collectively produce cold water that can be used to cool a processair stream. A process air plenum can receive the hot process air fromthe enclosed space. The cold water from the LAMEE and the recovery coilcan be delivered into the process air plenum to provide air cooling tothe hot process air. In an example, the cold water can circulate througha liquid-to-air heat exchanger configured to cool the hot process airwith the cold water.

Conditioning systems having the three components described above canoperate in multiple modes for both air cooling and liquid cooling, aswell as for the various pre-cooler designs. The inclusion of apre-cooler in the conditioning systems can eliminate the need forsupplemental mechanical cooling in some cooling applications.

This overview is intended to provide an overview of subject matter inthe present application. It is not intended to provide an exclusive orexhaustive explanation of the invention. The detailed description isincluded to provide further information about the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1A is a schematic of an example conditioning system for providingliquid cooling.

FIG. 1B is a schematic of an example conditioning system for providingliquid cooling.

FIG. 2 is a schematic of an example conditioning system for providingair cooling.

FIG. 3 is a schematic of an example conditioning system having apartially decoupled pre-cooler design.

FIG. 4 is a schematic of another example conditioning system having apartially decoupled pre-cooler design.

FIG. 5 is a schematic of an example conditioning system having a whollyor fully decoupled pre-cooler design.

FIG. 6 is a schematic of another example conditioning system having awholly decoupled pre-cooler design.

FIG. 7 is a schematic of a process cooling unit of an exampleconditioning system having a wholly decoupled pre-cooler design.

FIG. 8 is a schematic of an auxiliary cooling unit for the exampleconditioning system of FIG. 7.

FIG. 9 is a schematic of another example conditioning system having awholly decoupled pre-cooler design with process cooling units and anauxiliary cooling unit.

FIG. 10 is a schematic of another example conditioning system withprocess cooling units and an auxiliary cooling unit capable of operatingas a process cooling unit.

FIG. 11 is a schematic of an example conditioning system for providingliquid cooling.

FIG. 12 is a flowchart of an example method of operating a conditioningsystem in accordance with the present application.

DETAILED DESCRIPTION

The present application relates to conditioning systems and methods forproviding cooling to a heat load. The heat load can be any type ofdevice or system that generates heat. The device or system can beenclosed or open to the atmosphere. In an example, the heat load can befrom a data center. The conditioning systems and methods of the presentapplication include an evaporative cooler arranged in a scavenger airplenum with a pre-cooler arranged upstream of the evaporative cooler anda recovery coil arranged downstream of the evaporative cooler. Theconditioning systems of the present application can use outdoor air(scavenger air) that can be conditioned in the evaporative cooler suchthat the scavenger air can provide cooling to a cooling fluidcirculating through the recovery coil. The reduced-temperature coolingfluid exiting the recovery coil can be used to provide liquid cooling orair cooling to the heat load.

The design and arrangement of the three components (pre-cooler,evaporative cooler and recovery coil) in the scavenger air plenum canallow for the conditioning systems described herein to operate inmultiple modes, depending in part on the outdoor air conditions. Therecovery coil can be used in each of the modes to reduce a temperatureof the cooling fluid. The evaporative cooler and pre-cooler can beoptionally used, depending on the operating mode. In an example, theevaporative cooler can cool the scavenger air, as well as an evaporativefluid that can be collected and provide liquid cooling or air cooling incombination with the cooling fluid from the recovery coil. In anotherexample, the evaporative cooler can be configured primarily to conditionthe scavenger air, which can then cool the cooling fluid in the recoverycoil, and the evaporative fluid from the evaporative cooler is notcollected for process cooling. In an example, the evaporative cooler canbe configured to selectively operate in an adiabatic mode with a closedevaporative fluid cooling circuit. The various modes of operation aredescribed below. Various types of evaporative coolers usable in theconditioning systems of the present application are described below.

The pre-cooler can be configured to circulate a cooling fluid in orderto condition the scavenger air prior to passing the scavenger airthrough the evaporative cooler. The inclusion of the pre-cooler caneliminate the need for supplemental mechanical cooling in some coolingapplications. In an example, the cooling fluid circuit for thepre-cooler can be coupled with the cooling fluid circuit for theevaporative cooler and recovery coil (process cooling fluid), which isused to provide liquid or air cooling to the heat load. In anotherexample, the cooling fluid circuit for the pre-cooler can be partiallyor wholly decoupled from the process cooling fluid circuit.

FIG. 1A illustrates an example conditioning system 100A for providingcooling to a heat load 102A. The conditioning system 100A can include ascavenger air plenum 104A which can include an air inlet 106A and an airoutlet 108A through which a scavenger air stream can flow. The plenum104A can also be referred to as a housing, cabinet or structure, and canbe configured to house one or more components used to condition air orwater. Because the plenum 104A can house the components configured toprovide cooling, the plenum 104A can also be referred to herein as acooling system or cooling unit. The plenum 104A can be disposed outsideof an enclosed space having the heat load 102A or located external tothe devices that produce the heat load 102A.

The cooling system 104A can include a pre-cooler 160A, an evaporativecooler 110A, a dry coil (or cooling coil) 112A, and a fan (or fan array)114A, all of which can be arranged inside the cooling system or plenum104A. The dry coil or cooling coil 112A can also be referred to hereinas a recovery coil. The pre-cooler 160A can also be referred to hereinas a pre-cooling coil, a pre-cooler coil, a pre-conditioner or a drycoil. The pre-cooler 160A can be referred to herein as a first coolingcomponent (upstream of the evaporative cooler 110A) and the dry coil112A can be referred to herein as a second cooling component (downstreamof the evaporative cooler 110A). In some examples, a filter (not shown)can be arranged inside the scavenger plenum 104A near the air inlet106A. A filter can similarly be included in the scavenger plenum ofother example conditioning systems in accordance with this disclosure.

The scavenger air entering the plenum 104A can pass through a pre-cooler160A to precondition the scavenger air. The pre-cooler 160A is discussedfurther below. The scavenger air exiting the pre-cooler 160A can thenpass through the evaporative cooler 110A. The evaporative cooler 110Acan be configured to condition the scavenger air passing there throughusing an evaporative fluid, such as water. The evaporative cooler 110Acan use the cooling potential in both the air and the evaporative fluidto reject heat. In an example, as scavenger air flows through theevaporative cooler 110A, the evaporative fluid, or both the scavengerair and the evaporative fluid, can be cooled to a temperatureapproaching the wet bulb (WB) temperature of the air leaving thepre-cooler 160A. Due to the evaporative cooling process in theevaporative cooler 110A, a temperature of the evaporative fluid at anoutlet 118A of the evaporative cooler 110A can be less than atemperature of the evaporative fluid at an inlet 116A of the evaporativecooler 110A; and a temperature of the scavenger air at an outlet of theevaporative cooler 110A can be less than a temperature of the scavengerair at an inlet of the evaporative cooler 110A. In some cases, atemperature reduction of the evaporative fluid can be significant,whereas in other cases, the temperature reduction can be minimal.Similarly, a temperature reduction of the scavenger air can rangebetween minimal and significant. In some cases, the scavenger airtemperature can increase across the evaporative cooler 110A. Suchtemperature reduction of one or both of the evaporative fluid and thescavenger air can depend in part on the outdoor air conditions(temperature, humidity), operation of the pre-cooler 160A, and operationof the evaporative cooler 110A. For example, as described below andshown in FIG. 1B, in an example, the evaporative cooler 110B canselectively operate adiabatically, in which case a temperature of theevaporative fluid circulating through the evaporative cooler 110B canremain relatively constant or undergo minimal changes.

The evaporative cooler 110A can be any type of evaporative coolerconfigured to exchange energy between an air stream and a cooling fluidthrough evaporation of a portion of the fluid into the air. Evaporativecoolers can include direct-contact evaporation devices in which theworking air stream and the liquid water (or other fluid) stream that isevaporated into the air to drive heat transfer are in direct contactwith one another. In what is sometimes referred to as “open”direct-contact evaporation devices, the liquid water may be sprayed ormisted directly into the air stream, or, alternatively the water issprayed onto a filler material or wetted media across which the airstream flows. As the unsaturated air is directly exposed to the liquidwater, the water evaporates into the air, and, in some cases, the wateris cooled.

Such direct-contact evaporation devices can also include what issometimes referred to as a closed circuit device. Unlike the opendirect-contact evaporative device, the closed system has two separatefluid circuits. One is an external circuit in which water isrecirculated on the outside of the second circuit, which is tube bundles(closed coils) connected to the process for the hot fluid being cooledand returned in a closed circuit. Air is drawn through the recirculatingwater cascading over the outside of the hot tubes, providing evaporativecooling similar to an open circuit. In operation the heat flows from theinternal fluid circuit, through the tube walls of the coils, to theexternal circuit and then by heating of the air and evaporation of someof the water, to the atmosphere.

These different types of evaporative coolers can also be packaged andimplemented in specific types of systems. For example, a cooling towercan include an evaporative cooling device such as those described above.A cooling tower is a device that processes working air and water streamsin generally a vertical direction and that is designed to reject wasteheat to the atmosphere through the cooling of a water stream to a lowertemperature. Cooling towers can transport the air stream through thedevice either through a natural draft or using fans to induce the draftor exhaust of air into the atmosphere. Cooling towers include orincorporate a direct-contact evaporation device/components, as describedabove.

Examples of evaporative coolers usable in the conditioning systems ofthe present application can also include other types of evaporativecooling devices, including liquid-to-air membrane energy exchangers.Unlike direct-contact evaporation devices, a liquid-to-air membraneenergy exchanger (LAMEE) separates the air stream and the liquid waterstream by a permeable membrane, which allows water to evaporate on theliquid water stream side of the membrane and water vapor molecules topermeate through the membrane into the air stream. The water vapormolecules permeated through the membrane saturate the air stream and theassociated energy caused by the evaporation is transferred between theliquid water stream and the air stream by the membrane.

Membrane exchangers may have some advantages over other types ofevaporative coolers. For example, the LAMEE may eliminate or mitigatemaintenance requirements and concerns of conventional cooling towers orother systems including direct-contact evaporation devices, where thewater is in direct contact with the air stream that is saturated by theevaporated water. For example, the membrane barriers of the LAMEEinhibit or prohibit the transfer of contaminants and micro-organismsbetween the air and the liquid stream, as well as inhibiting orprohibiting the transfer of solids between the water and air. The use ofa LAMEE as the evaporative cooler in the conditioning system isdescribed further below, including in reference to the conditioningsystem of FIG. 4. However, as noted above, depending upon theapplication and a number of factors, examples according to thisdisclosure can include any type of evaporative cooler configured toexchange energy between an air stream and a cooling fluid throughevaporation of a portion of the fluid into the air.

In an example, as shown in FIG. 1A, the evaporative fluid from theevaporative cooler 110A can be collected and delivered to a tank 122Aand thus can be used to provide cooling for the heat load 102A. In otherexamples described herein, the evaporative fluid from the evaporativecooler 110A is not collected for cooling the heat load 102A. See, forexample, conditioning system 1100 in FIG. 11 and described below. In yetother examples, the conditioning system can be configured to switchbetween the configuration shown in FIG. 1A (in which the evaporativefluid exiting the evaporative cooler 110A is collected and transportedto the tank 122A) and operating the evaporative cooler 110Aadiabatically to circulate the evaporative fluid through the evaporativecooler 110A only. This is shown in FIG. 1B and described below.

In an example, the evaporative fluid in the evaporative cooler 110A canbe water or predominantly water. In the conditioning system 100A of FIG.1A, the cooling fluid is described as being water but the inlet 116A andoutlet 118A can be described as a cooling fluid inlet and a coolingfluid outlet since a fluid in addition to, or as an alternative to,water can circulate through the evaporative cooler 110A. It isrecognized that other types of evaporative cooling fluids can be used incombination with water or as an alternative to water in the otherconditioning systems described herein.

The dry coil or recovery coil 112A can be arranged inside the plenum104A downstream of the evaporative cooler 110A. The recovery coil 112Acan cool a cooling fluid circulating through the recovery coil 112Ausing the cooling potential of the scavenger air. The scavenger airexiting the evaporative cooler 110A can be relatively cool andadditional sensible heat from the cooling fluid passing through therecovery coil 112A can be rejected into the scavenger air. The recoverycoil 112A can produce a reduced-temperature cooling fluid that canprovide cooling to the heat load 102A. The reduced-temperature coolingfluid exiting the recovery coil 112A can flow to the evaporative cooler110A or to a water tank 122A. The flow path of the cooling fluid to andfrom the recovery coil 112A is described below. The scavenger airexiting the recovery coil 112A can be directed out of the plenum 104Ausing the fan 114A and can exit the plenum 104A at the outlet 108A asexhaust.

In an example, the cooling fluid circulating through the recovery coil112A can be water. In an example, the cooling fluid circulating throughthe recovery coil 112A can be the same fluid as the evaporative fluid inthe evaporative cooler 110A.

As provided above, in an example, the evaporative fluid in theevaporative cooler 110A can be water. In an example, as shown in FIG.1A, the reduced-temperature water from the outlet 118A of theevaporative cooler 110A can be used to provide cooling to the heat load102A. The reduced-temperature water can flow from the outlet 118A to thewater tank 122A via a water line 120A. Although not shown in FIG. 1A,the water tank 122A can include a make-up valve and a drain valve tomaintain the water level and hardness level inside the tank 122A. Thewater tank 122A can include one or more temperature sensors in or aroundthe water tank 122A to monitor a temperature of the water in the tank122A. In an example, a control of the conditioning system 100A can bebased, in part, on a measured temperature of the water in the tank 122Acompared to a set point water temperature. In an example, the set pointwater temperature can be pre-determined based on an estimated quantityof the heat load 102A. In an example, the set point water temperaturecan vary during operation of the conditioning system 100A, based in parton operation of the data center or other devices that produce the heatload 102A.

The water from the water tank 122A can be pumped with a pump 124A to theheat load 102A via a water line 126A. Alternatively, the water from thetank 122A can be pumped to a cold water supply main configured to feedthe cold water to the heat load 102A. As described further below, thereduced-temperature water can provide cooling to the heat load 102A bytransporting the water to the heat load 102A. In an example in which thehead load 102A includes hot air from an enclosed space, the design ofthe conditioning system 100A can eliminate the steps of moving hotsupply air from the enclosed space through the cooling system 104A andthen back to the enclosed space. The reduced-temperature water canprovide cooling to the heat load 102A using any known methods to rejectheat from air or one or more devices, such methods can include, but arenot limited to, liquid immersing technology, cold plate technology, reardoor heat exchangers, cooling distribution units (CDU), and coolingcoils. In an example, the water can directly cool one or more componentsproducing the heat load 102A. The one or more components can include,but are not limited to, electrical components. In an example in whichthe heat load 102A comes from an enclosed space, the water can passthrough one or more cooling coils placed in a path of the supply air inthe enclosed space, and the water in the cooling coils can sensibly coolthe supply air.

After the water provides cooling to the heat load 102A, the water can berecirculated back through the cooling system 104A. The water can be atan increased-temperature after providing cooling to the heat load 102Abecause the rejected heat from the heat load 102A has been picked up bythe water. The increased-temperature water can be transported to the drycoil 112A through a water line 128A. Alternatively, the water can betransported to a hot water return configured to transport theincreased-temperature water back to the dry coil 112A. As providedabove, the dry coil 112A can cool the water using the scavenger airexiting the evaporative cooler 110A.

The water can exit the dry coil 112A at a reduced temperature through awater line 130A, which can be split, using a bypass valve 132A, into awater line 180A to the evaporative cooler 110A and a water line 129A tothe tank 122A. The bypass valve 132A can control how much of the waterexiting the dry coil 112A is sent to the evaporative cooler 110A and howmuch is sent to the tank 122A, depending on an operating mode of theconditioning system 100A.

In an economizer mode, the bypass valve 132A can be open such that allof the water from the dry coil 112A can bypass the evaporative cooler110A and go directly to the tank 122A. The economizer mode or wintermode can enable the conditioning system 100A to cool the water using thescavenger air and dry coil 112A, without having to run the evaporativecooler 110A. In that situation, there may be no need for evaporationinside the evaporative cooler 110A since the cold outdoor air (scavengerair) can pass through the dry coil 112A and sufficiently cool the water.The dry coil 112A can also be referred to herein as an economizer coilsince it can be a primary cooling source for the water in the economizermode. Three modes of operation are described further below for operatingthe conditioning system 100A.

In another example, instead of the bypass valve 132A controlling a flowbetween the evaporative cooler 110A and the tank 122A, the conditioningsystem can include two separate tanks or two separate tank sections.This is described below in reference to FIGS. 1B and 6.

The pre-cooler 160A, located upstream of the evaporative cooler 110A,can be used to pre-condition the scavenger air entering the plenum 104A,prior to passing the scavenger air through the evaporative cooler 110A.The pre-cooler 160A can be effective when the temperature of the waterentering the pre-cooler 160A is lower than the outdoor air dry bulbtemperature. The pre-cooler 160A can be used in typical summerconditions as well as in extreme summer conditions when the outdoor airis hot and humid. The pre-cooler 160A can depress the outdoor air wetbulb temperature, thus pre-cooling the scavenger air and heating thewater. The pre-cooler 160A can provide more cooling potential in theevaporative cooler 110A.

In an example as shown in FIG. 1A, the pre-cooler 160A can use waterfrom the tank 122A to condition the scavenger air. A pump 172A can pumpwater from the tank 122A to the pre-cooler 160A through a water line174A. (Thus the reduced temperature water in the tank 122A can leave thetank 122A through two different water lines—line 126A to the heat load102A and line 174A to the pre-cooler 160A.) In other examples, one waterline and one pump can be used to deliver water out of the tank 122A anda split valve can be used to control the delivery of water to the heatload 102A and to the pre-cooler 160A.

In an example, reduced temperature water is described above as beingdelivered to the heat load (an enclosed space or a device) for providingliquid cooling. In other examples, instead of delivering water from thetank 122A to the heat load, the reduced temperature water can bedelivered to a liquid to liquid heat exchanger (LLHX) to use the waterto reduce a temperature of a secondary coolant circulating through theLLHX. The secondary coolant can be configured to provide cooling to theenclosed space or one or more devices, and the coolant can receive theheat rejected from the enclosed space or one or more devices, resultingin a temperature increase of the secondary coolant. The reducedtemperature water can provide cooling to the increased temperaturesecondary coolant such that the secondary coolant can be delivered backto the enclosed space or one or more devices for continued cooling.Reference is made to International Application No. PCT/CA2016/050252,filed on Mar. 8, 2016, which is incorporated by reference herein anddiscloses an example of a design with a secondary coolant and LLHX.

Because the pre-cooler 160A uses water from the tank 122A as the coolingfluid in the pre-cooler 160A, the design of the pre-cooler 160A as shownin FIG. 1A can be referred to herein as a coupled pre-cooler. In otherwords, the pre-cooler 160A is designed and configured to use a portionof the reduced-temperature water produced by the recovery coil 112A orthe evaporative cooler 110A (and intended for cooling the heat load102A) as the cooling fluid for the pre-cooler 160A. In other examplesillustrated and described herein, a cooling fluid circuit for thepre-cooler 160A can be partially or wholly decoupled from the processcircuit for the evaporative cooler 110A and recovery coil 112A. In thatcase, the pre-cooler 160A can have an external cooling circuit partiallyor wholly separate from the reduced-temperature water produced by theevaporative cooler 110A or recovery coil 112A for process cooling.

In an example, and as shown in FIG. 1A, the plenum 104A can include twosets of bypass dampers—first dampers 176A between the pre-cooler 160Aand the evaporative cooler 110A, and second dampers 134A between theevaporative cooler 110A and the dry coil 112A. The use of the bypassdampers 176A and 134A to direct the flow of scavenger air into theplenum 104A can depend on the outdoor air conditions. Although the firstand second bypass dampers 176A and 134A are each shown as having a pairof dampers on opposing sides of the plenum 104A, it is recognized thatone or both of the first 176A and second 134A bypass dampers can be asingle damper on one side of the plenum 104A.

The conditioning system 100A can operate in at least three modes andselection of the mode can depend, in part, on the outdoor air conditionsand the quantity of the heat load 102A. When the outdoor air is cold,the conditioning system 100A can operate in a first mode, an economizermode, and the pre-cooler 160A and the evaporative cooler 110A can bebypassed. The scavenger air can enter the plenum 104A through thedampers A134 and pass through the dry coil 112A. This can protect theevaporative cooler 110A and avoid running the evaporative cooler 110Awhen it is not needed. In the first mode or economizer mode, thescavenger air can be cool enough such that the dry coil 112A can provideall cooling to the cooling fluid (water) delivered to the tank 122A toprovide cooling to the heat load 102, without needing to operate theevaporative cooler 110A.

In a second operating mode, which can also be referred to as a normalmode or an evaporation mode, the pre-cooler 160A can be bypassed but theevaporative cooler 110A can be used. The evaporation mode can operateduring mild conditions, such as spring or fall, when the temperature orhumidity is moderate, as well as during some summer conditions. Thescavenger air may be able to bypass the pre-cooler 160A, while stillmeeting the cooling load. The scavenger air can enter the plenum 104Athrough dampers 176A, and then can pass through the evaporative cooler110A and the dry coil 112A. The conditioning system 100A can modulatebetween a normal mode and an economizer mode to limit power consumptionand based on outdoor air conditions. In another example, the dampers176A can be excluded from the system 100A or the dampers 176A may not beused in some cases. In such example, during the second operating mode,the scavenger air can enter through the inlet 106A and pass through thepre-cooler 160A but the pre-cooler 160A can be turned off such that thewater or cooling fluid is not circulating through the pre-cooler 160A.

In a third operating mode, which can also be referred to as an enhancedmode or a super-evaporation mode, the conditioning system 100A can runusing both the pre-cooler 160A and the dry coil 112A. Under extremeconditions, or when the outdoor air is hot or humid, the cooling system104A can provide pre-cooling to the scavenger air, using the pre-cooler160A, before the scavenger air enters the evaporative cooler 110A. Thepre-cooler 160A can be used to improve the cooling power of the system104A, allowing the evaporative cooler 110A to achieve lower dischargetemperatures at the outlet 118A of the evaporative cooler 110A. Thepre-cooler 160A can reduce or eliminate a need for supplementalmechanical cooling.

The water exiting the pre-cooler 160A can be directed to the inlet 116Aof the evaporative cooler 110A through a water line 178A. A junction181A of the water lines 178A and 180A is shown in FIG. 1A. It isrecognized that the water lines 178A and 180A do not have to merge orjoin together prior to the inlet 116A and two separate water lines canbe in fluid connection with the inlet 116A.

As provided above, the cooling fluid circuit of the pre-cooler 160A ofFIG. 1A can be coupled with the evaporative cooler 110A since thecooling fluid for the pre-cooler 160A comes from the water in the tank122A, which is produced by the evaporative cooler 110A. The pre-cooler160A is further coupled in the design of FIG. 1A given that the coolingfluid, after exiting the pre-cooler 160A, flows through the evaporativecooler 110A.

The conditioning system 100A can include a system controller 148A tocontrol operation of the conditioning system 100A and control an amountof cooling provided from the cooling system 104A to the heat load 102A.The system controller 148A can be manual or automated, or a combinationof both. The conditioning system 100A can be operated so that atemperature of the water in the tank 122A can be equal to a set pointtemperature that can be constant or variable. In a conditioning system100A including a LLHX and a secondary coolant loop, the conditioningsystem 100A can be operated so that a temperature of the coolant leavingthe LLHX can be equal to a set point temperature that can be constant orvariable. Controlling to the temperature of the coolant can be inaddition to or as an alternative to controlling to the temperature ofthe water in the tank 122A or the water leaving the tank 122A. The setpoint temperature can be determined based in part on the coolingrequirements of the heat load 102A. Water or coolant delivered to theheat load 102A from the cooling system 104A can cool the air in anenclosed space or cool one or more electrical components that can beenclosed or open to the atmosphere. The conditioning system 100A can becontrolled to reduce overall water usage and power consumption, andincrease heat rejection from the heat load 102A. The system controller148A is described in further detail below.

Operation of the conditioning system 100A can be aimed at increasing theportion of sensible heating between the water and the scavenger air anddecreasing the portion of latent heating between the water and thescavenger air. Water evaporation inside the evaporative cooler 110A canbe optimized to minimize water consumption in the cooling system 104A byat least one of using cooling coils before or after the evaporativecooler 110A and modulating a scavenger air flow rate through the system104A. A greater portion of the heat load can be rejected in the dry coil112A downstream of the evaporative cooler 110A, if the water returningto the system 104A is at a higher temperature. As a result, thescavenger air temperature at an outlet of the dry coil 112A can behigher. The evaporative cooler 110A can consume less water when thelatent portion of the work performed in the evaporative cooler 110A isreduced.

In an example, the conditioning system 100A can be operated in aneconomizer mode in which the evaporative cooler 110A is turned off andbypassed so long as the set point temperature of the water delivered tothe tank 122A can be met using the dry coil 112A. However, if the waterin the tank is at a temperature above the set point, the conditioningsystem 100A can be operated in a normal mode which includes using theevaporative cooler 110A to cool the water. Similarly, if the set pointtemperature cannot be achieved in the normal mode, an enhanced mode caninclude using the pre-cooler 160A to condition the scavenger air beforethe scavenger air enters the evaporative cooler 110A.

The reduced-temperature water from the recovery coil 112A or evaporativecooler 110A can be part of a cooling fluid circuit that can extend fromthe plenum 104A and be delivered to the heat load 102A. After the waterprovides cooling to the heat load 102A, the water can be recirculatedthrough the cooling system 104A. One or both of the tank 122A and pump124A can be located physically in the cooling system or plenum 104A, orone or both of the tank 122A and pump 124A can be physically located inan enclosed space that produces the heat load 102A. Alternatively, oneor both of the tank 122A and pump 124A can be located in a structureseparate from the cooling system or plenum 104A and the heat load 102A.Each of the water lines 129A, 130A, 178A and 180A can be inside oroutside the plenum 104A, or partially inside and partially outside theplenum 104A. A location of the other water lines relative to the plenum104A can depend in part on whether the tank 122A is inside or outside ofthe plenum 104A.

As provided above, the water line 126A can transport the water from thetank 122A to a cold water supply main, which can deliver the water tothe heat load 102A. As described further below, in an example, the heatload 102A can utilize multiple cooling systems 104A for cooling and thecold water supply can be fluidly connected to each cooling system 104A.

The system controller 148A can include hardware, software, andcombinations thereof to implement the functions attributed to thecontroller herein. The system controller 148A can be an analog, digital,or combination analog and digital controller including a number ofcomponents. As examples, the controller 148A can include ICB(s), PCB(s),processor(s), data storage devices, switches, relays, etcetera. Examplesof processors can include any one or more of a microprocessor, acontroller, a digital signal processor (DSP), an application specificintegrated circuit (ASIC), a field-programmable gate array (FPGA), orequivalent discrete or integrated logic circuitry. Storage devices, insome examples, are described as a computer-readable storage medium. Insome examples, storage devices include a temporary memory, meaning thata primary purpose of one or more storage devices is not long-termstorage. Storage devices are, in some examples, described as a volatilememory, meaning that storage devices do not maintain stored contentswhen the computer is turned off Examples of volatile memories includerandom access memories (RAM), dynamic random access memories (DRAM),static random access memories (SRAM), and other forms of volatilememories known in the art. The data storage devices can be used to storeprogram instructions for execution by processor(s) of the controller148A. The storage devices, for example, are used by software,applications, algorithms, as examples, running on and/or executed by thecontroller 148A. The storage devices can include short-term and/orlong-term memory, and can be volatile and/or non-volatile. Examples ofnon-volatile storage elements include magnetic hard discs, opticaldiscs, floppy discs, flash memories, or forms of electricallyprogrammable memories (EPROM) or electrically erasable and programmable(EEPROM) memories.

The system controller 148A can be configured to communicate with theconditioning system 100A and components thereof via various wired orwireless communications technologies and components using various publicand/or proprietary standards and/or protocols. For example, a powerand/or communications network of some kind may be employed to facilitatecommunication and control between the controller 148A and theconditioning system 100A. In one example, the system controller 148A cancommunicate with the conditioning system 100A via a private or publiclocal area network (LAN), which can include wired and/or wirelesselements functioning in accordance with one or more standards and/or viaone or more transport mediums. In one example, the system 100A can beconfigured to use wireless communications according to one of the 802.11or Bluetooth specification sets, or another standard or proprietarywireless communication protocol. Data transmitted to and from componentsof the system 100A, including the controller 148A, can be formatted inaccordance with a variety of different communications protocols. Forexample, all or a portion of the communications can be via apacket-based, Internet Protocol (IP) network that communicates data inTransmission Control Protocol/Internet Protocol (TCP/IP) packets, over,for example, Category 5, Ethernet cables.

The system controller 148A can include one or more programs, circuits,algorithms or other mechanisms for controlling the operation of theconditioning system 100A. For example, the system controller 148A can beconfigured to modulate the speed of the fan 114A and/or controlactuation of the valve 132A to direct cooling fluid from the outlet ofthe dry coil 112A to either the inlet 116A of evaporative cooler 110A orthe tank 122A. The system controller 148A can also be configured tooperate the system 100A in the three modes described above.

A system controller is not specifically shown in all of the figures forthe various conditioning systems described below. However, it isrecognized that the other conditioning systems can include a systemcontroller that operates similar to the system controller 148A of FIG.1A described above.

The cooling system 104A can maximize the cooling potential in theevaporative cooler 110A and modulate the scavenger air through theplenum 104A based on the outdoor air conditions. The economizer mode,for example, in winter, can provide a reduction in water usage and powerconsumption compared to conventional cooling systems.

The cooling system 104A can utilize reduced-temperature water (from thedry coil 112A or the evaporative cooler 110A) to provide cooling to theheat load 102A. In an example, the heat load 102A can be a data centeror other enclosed space. The reduced-temperature water can betransported from the cooling system 104A, which is disposed outside ofthe data center, to the data center or other enclosed space. Incontrast, for existing air cooling designs, process air from the datacenter can be delivered to the cooling system which can be configured asa larger unit for two air flow paths—the process air and the scavengerair. Thus more energy is used in those designs to move the process airfrom the data center to the cooling system and then condition theprocess air. In the systems described herein, less energy by comparisoncan be used to deliver the reduced-temperature water from the coolingsystem to the data center. Moreover, water has a higher thermal capacitythan air; thus a lower flow rate of water can be used, compared to air,to reject a certain amount of heat directly from one or more electricalcomponents in the data center (or other components needing cooling) orfrom the air in the data center.

In an example, the heat load 102A can be a device that can be in anenclosed space or a device that can be open to the atmosphere. Thereduced-temperature water or coolant from the cooling system 104A can bedelivered to the device. The cooling system 104A can be located separatefrom and remote to the device and the reduced-temperature water orcoolant can be transported or delivered to the device. In an example,the device is not in an enclosed space, such that the device can be opento the atmosphere and an exterior of the device can be exposed tooutdoor air. The conditioning system 100A can be configured such thatthe reduced-temperature water or coolant from the cooling system 104Acan be delivered to an inlet of the device at an inlet temperature. Thecooling liquid can reject heat from the device such that the water orcoolant leaving the device at an outlet can be at an outlet temperaturethat is higher than the inlet temperature. The increased-temperatureliquid exiting the device can be recirculated back to the cooling system104A where the water or coolant can be cooled again, as described above.

In an example, the device can include any type of equipment or componentthat generates heat or any type of equipment or component that uses afluid for heat rejection. The reduced-temperature water or coolant fromthe cooling system 104A can reject heat from the device using any knownmethod, including those described above and shown herein. In an example,the reduced-temperature water or coolant can directly cool the device.The reduced-temperature water or coolant from the cooling system 104Acan circulate through channels formed in the device. In an example, thereduced-temperature water or coolant can be circulated through a liquidto liquid heat exchanger (LLHX) inside the device and the water orcoolant can pick up heat from a second fluid circulating through theLLHX to reduce a temperature of the second fluid. The device caninclude, but is not limited to, industrial equipment, commercialequipment, a chiller, a condenser coil, or any equipment (or in anyprocess) using a cooling tower for heat rejection. The device caninclude any type of equipment or component that can use water or anothercooling fluid to reject heat from the equipment/component or from aliquid in, or associated with, the equipment/component.

It is recognized that the cooling system 104A can be used to providecooling to more than one device, depending on a quantity of the heatload for each of the devices and a cooling capacity of the system 104A.In an example, the device can include a plurality of pieces ofindustrial equipment; each piece of equipment can receivereduced-temperature water or coolant which can come from a centralcooling system 104A or from a separate cooling system 104A dedicated toeach piece of equipment.

The term “providing cooling to a heat load” as used herein refers tousing the reduced-temperature water (or other type of coolant) from therecovery coil 112A (and in some cases the evaporative cooler 110A) toprovide cooling to air in an enclosed space or to provide cooling to oneor more devices or components (within an enclosed space or open to theatmosphere). The term “providing cooling to a heat load” as used hereincan also refer to using the reduced-temperature water (or other type ofcoolant) to reduce a temperature of a secondary coolant in a liquid toliquid heat exchanger, the secondary coolant being used to receive heatrejected from the enclosed space or one or more devices. The devices orcomponents can be directly cooled with the reduced-temperature water orcoolant, the air around the components can be cooled (if containedwithin an enclosed space), or a combination can be used. Although thepresent application focuses on a data center as an example of anenclosed space with a heat load, the systems and methods disclosedherein for cooling can be used in other examples of enclosed spaces,including for example, a telecommunication room, industrial applicationsand commercial spaces. The systems and methods disclosed herein can beused in any application using water for cooling and then a coolingtower, or any application using dry coolers in combination with asupplemental heat rejection system for high scavenger air dry bulbtemperatures. Reference is made to International Application No.PCT/CA2016/050252, filed on Mar. 8, 2016, which is incorporated byreference herein and provides further examples of cooling applicationsthat can utilize the methods and systems disclosed herein.

FIG. 1B illustrates another example conditioning system 100B forproviding liquid cooling to a heat load 102B. The conditioning system100B can be similar in many aspects to the conditioning system 100A ofFIG. 1A and can include a pre-cooler 160B, an evaporative cooler 110B, adry coil 112B and a fan 114B, all of which can be arranged within ascavenger plenum 104B as described above for the system 100A. However,in contrast to the conditioning system 100A of FIG. 1A, the conditioningsystem 100B can have two separate water tanks, as well as an additionalpump and flow path to the evaporative cooler 110B. As described below,the design in FIG. 1B can allow for additional operating modes of thesystem 100B, as compared to the system 100A. The system 100B can includea system controller 148B that can be similar to the system controller148A described above for the system 100A.

The conditioning system 100B can include a first tank 122B and a secondtank 123B. The first tank 122B can be generally configured to provideliquid cooling to a heat load 102 and the second tank 123B can begenerally configured as the water supply for the evaporative cooler110B. However, each of tanks 122B and 123B can receive water from theevaporative cooler 110B and the recovery coil 112B, depending on anoperating mode of the system 100B.

In an example, the first tank 122B can be fluidly connected to the heatload 102B such that the reduced-temperature water can flow from the tank122B to the heat load 102B through a water line 126B using a pump 124B,as configured with the system 100A. In another example, water can drainout of the tank 122B to another external collection reservoir, where itcan then be pumped to the heat load 102B. This can eliminate a supplypump (124B) inside the cooling unit 104B.

The increased-temperature water leaving the heat load 102B can bereturned to the recovery coil 112B (via a water line 128B) in order tocool the increased temperature water, which can then exit the recoverycoil 112B through a water line 130B. The flow path into and out of therecovery coil 112B can be the same as in the system 100A. However, abypass valve 132B can control distribution of the reduced-temperaturewater either to the first tank 122B through a water line 129B or to thesecond tank 123B through a water line 180B. This is different from thesystem 100A in which the bypass valve 132A can direct water in the waterline 130A to the evaporative cooler 110A directly, rather than to thesecond tank 123B as shown in FIG. 1B. As provided below, a position ofthe valve 132B can depend on the operating mode of the system 100B.

The second tank 123B can provide water to an inlet 116B of theevaporative cooler 110B using a pump 154B and a water line 121B. Theseparation of the two tanks 122B and 123B in the design of FIG. 1B canreplace the junction 181A of the design of FIG. 1A. Moreover, the designof FIG. 1B having the two tanks 122B and 123B can facilitate operationof the evaporative cooler 110B in an evaporation mode and an adiabaticmode, as described further below.

After flowing through the evaporative cooler 110B, the water can exitthe evaporative cooler 110B through a water line 120B. A bypass valve182B can control the distribution of water from the evaporative cooler110B to the first tank 122B (via a water line 135B) and the second tank123B (via a water line 131B). The valve 182B is not included in thedesign of FIG. 1A and is described further below in reference to theoperating modes of the system 100B.

As provided above in reference to the system 100A, the pre-cooler 160Bcan selectively be used depending on the outdoor air conditions and anoperating mode of the system 100B. Similar to the design of the system100A, the pre-cooler 160B can receive reduced-temperature water from thefirst tank 122B using a pump 172B and water line 174B. The water canexit the pre-cooler 160B at an increased temperature. In contrast to thedesign of the system 100A, the increased-temperature water from thepre-cooler 160B can be directed to the second tank 123B through a waterline 178B, rather than through the evaporative cooler 110B. Similar tothe design of the system 100A, the pre-cooler 160B of the system 100B,as shown in FIG. 1B, can have a coupled design and the cooling fluid forthe pre-cooler 160B can come from the first tank 122B. In otherexamples, the pre-cooler 160B can be partially or fully decoupled (see,for example, FIGS. 3-6).

In an example, the system 100B can operate in the three modes describedabove for the system 100A, but the system 100B can also operate in atleast two additional modes as compared to the system 100A.

In an economizer mode (first mode of the system 100A), only the recoverycoil 112B is used to cool the water or other cooling fluid that providesliquid cooling to the heat load 102B. The cold water exiting therecovery coil 112B can pass through the three-way valve 132B which candivert essentially all of the water in the water line 130B to the firsttank 122B. The first tank 122B can supply the cold water to the heatload 102B using the pump 124B. In the economizer mode, the pumps 154Band 172B can be turned off since the evaporative cooler 110B andpre-cooler 160B are not being used. The scavenger air can enter theplenum 104B through the bypass dampers 134B.

The system 100B can operate in an adiabatic mode that can considered tobe between the economizer mode and the evaporation mode (second mode ofthe system 100A) in terms of the energy usage of the system 100B and thecooling requirements needed by the heat load 102B. The bypass valve 132Bcan be in the same position and the delivery of cold water to the heatload 102B can be the same as described above in the economizer mode. Inthe adiabatic mode, the evaporative cooler 110B can be configured tocirculate water from the second tank 123B through the evaporative cooler110B in a closed fluid circuit. The pump 154B can be on and water can beprovided through the water line 121B to the inlet 116B of theevaporative cooler. The bypass valve 182B can be positioned such thatessentially all of the water exiting the evaporative cooler 110B at theoutlet 118B can be directed to the second tank 123B. Thus the flow ofwater through each of the evaporative cooler 110B and the recovery coil112B can be separate from one another via the two tanks 122B and 123B.In this adiabatic mode, the tank 123B can be essentially dedicated tothe recovery coil 112B and the tank 122B can be essentially dedicated tothe evaporative cooler 110B.

During operation of the evaporative cooler 110B in the adiabatic mode, atemperature of the water (or other cooling fluid) can remain generallyconstant or have minimal temperature fluctuations. The outdoor airconditions can be such that sufficient conditioning of the scavenger airstream can be provided by the water in the tank 123B throughrecirculation of the water in the closed fluid circuit. As the scavengerair passes through the evaporative cooler 110B, it can be cooledadiabatically such that its temperature can be reduced, but its humiditylevel can increase, while its overall enthalpy can remain constant. Thereduced-temperature air can be supplied to the recovery coil 112B andthe recovery coil 112B can supply water at the required temperature setpoint. This adiabatic process or mode can significantly reduce orminimize water consumption by the conditioning system 100B and can beused when operation of the system 100B in the economizer mode is notable to reach the set point temperature for the cold water supply to theheat load 102B.

In an evaporation mode (second mode of the system 100A), the evaporativecooler 110B can be switched over from operating adiabatically. Aposition of the bypass valve 132B can be changed to direct water fromthe recovery coil 112B to the second tank 123B. Similarly, a position ofthe bypass valve 182B can be changed to direct water from theevaporative cooler 110B to the first tank 122B. An equalization valve137B can be located between the two tanks 122B and 123B. The valve 137Bcan be closed during the economizer and adiabatic modes, and can beopened in the evaporation mode to stabilize the tank levels. Theevaporation mode in the system 100B can be similar to that describedabove for the system 100A in that the fluid circuit through theevaporative cooler 110B can be in fluid connection with the fluidcircuit through the recovery coil 112B.

In an example, in the evaporation mode, essentially all or a majority ofthe water from the recovery coil 112B can be redirected to the secondtank 123B and essentially all or a majority of the water from theevaporative cooler 110B can be redirected to the first tank 122B. Inanother example, in the evaporation mode, the distribution to each tank122B and 123B can be split for one or both of the water from theevaporative cooler 110B and the recovery coil 112B. In an example,instead of the equalization valve 137B, the tanks 122B and 123B can beseparated by a dividing wall (see, for example, FIG. 6) and a height ofthe wall can be lowered such that the wall can function as a weir. Ifone tank level rises too high, the water can spill over the weir intothe other tank.

During operation in the adiabatic and evaporation modes, the scavengerair can enter the plenum 104B at an inlet 106B and the pre-cooler 160Bcan be off In another example, the plenum 104B can include bypassdampers downstream of the pre-cooler 160B and upstream of theevaporative cooler 110B to bypass the pre-cooler 160B and direct thescavenger air into the evaporative cooler 110B.

In an enhanced mode or a super-evaporation mode (third mode of thesystem 100A), the pump 172B can be turned on to direct water through thepre-cooler 160B. The cold water for the pre-cooler 160B can come fromthe first tank 122B. After exiting the pre-cooler 160B at anincreased-temperature, the water can be delivered to the second tank123B. Similar to the system 100A, as shown in FIG. 1B, the pre-cooler160B can have a coupled design within the system 100B. In otherexamples, the pre-cooler 160B can have a partially decoupled or fullydecoupled design, as described below and shown in the figures.

The system 100B can be controlled to run at the lowest operating mode(in terms of energy and water usage) that is sufficient for meeting thecooling requirements for the heat load 102B. The design of the system100B can allow for an additional mode that can include operating theevaporative cooler 110B adiabatically and running the pre-cooler 160B.This mode can be considered somewhat of a hybrid mode that is generallybetween the adiabatic mode and the enhanced mode.

The conditioning systems 100A and 100B of FIGS. 1A and 1B can beconfigured to use the reduced-temperature water from the evaporativecooler 110A, 110B and recovery coil 112A, 112B to provide liquid coolingto the heat load 102A, 102B, which can come from an enclosed space, inone example.

FIG. 2 illustrates an example conditioning system 200 for providing aircooling to a process air stream from a data center or other enclosedspace. The conditioning system 200 can include many similar componentsand functions of the conditioning system 100A of FIG. 1A. Theconditioning system 200 can include a scavenger plenum 204, similar tothe plenum 104A of FIG. 1A, for receiving a scavenger air stream anddirecting the scavenger air from an air inlet 206 to an air outlet 208.The conditioning system 200 can include a process plenum 205 forreceiving a process air stream and directing the process air from aprocess air inlet 207 to a process air outlet 209. The scavenger plenum204 and process plenum 205 can be housed within a system cabinet 203,which can also house a tank 222, similar to the tank 122A, describedfurther below.

An interior of the scavenger plenum 204 can be configured similar to thescavenger plenum 104A and can include a pre-cooler 260, an evaporativecooler 210, a dry coil or recovery coil 212, and a scavenger fan (or fanarray) 214. The components in the scavenger plenum 204 can operatesimilar to as described above in reference to the conditioning system100A of FIG. 1A and the evaporative cooler 210 and recovery coil 212 canreduce a temperature of the cooling fluid passing there through suchthat a reduced-temperature cooling fluid can be provided to the tank 222and can ultimately be used for air cooling, as described below. Theconditioning system 200 can operate in multiple modes similar to themodes described above in reference to the conditioning system 100A, andselection of the mode can depend, in part, on the outdoor airconditions, as well as a cooling load for the process air stream, asdescribed below. In an example, the scavenger plenum 204 can includefirst dampers 276 and second dampers 234 to direct the flow of scavengerair into the plenum 204 depending on the operating mode. In anotherexample, the dampers 276 can be excluded from the design of the plenum204.

Rather than providing liquid cooling to a data center or other enclosedspace that needs cooling, the conditioning system 200 can be configuredto provide air cooling. Air from the data center or enclosed space canenter the system 200 through the process air inlet 207 of the processplenum 205. The hot aisle return air entering the process plenum 205 hasbeen heated in the data center or enclosed space and requires cooling toa target supply air temperature, which is generally determined based onthe amount and characteristics of equipment housed in the enclosedspace, for example, computing, networking, data storage and otherequipment. The heated process air can be cooled inside the processplenum 205 as described below. The reduced-temperature process air canthen exit the process plenum 205 through the process air outlet 209. Thereduced-temperature air (cold aisle supply) can be transported to thedata center or space at or within an acceptable tolerance of the targetsupply air temperature.

The scavenger and process plenums 204 and 205, respectively, can besealed from one another such that the scavenger and process air streamsdo not intermix with one another (other than ordinary leakage betweenthe two plenums, if collocated). The scavenger plenum 204 and processplenum 205 can be defined by partitioned sub-sections of the interiorspace of the system cabinet 203, as is schematically depicted in FIG. 2.In other examples, scavenger and process plenums 204 and 205 can beseparate from and mounted within the system cabinet 203. Although somecomponents of example systems in accordance with this disclosure areschematically depicted as outside of the overall system cabinet and/oroutside of the two separate plenums, at least in some examples all ofthe cooling/conditioning components of example system(s) are locatedwithin a single system enclosure, which can be conveniently packaged,transported, and installed. In such cases, the scavenger and processinlets and outlets can be connected directly to or indirectly viaappropriate ducting or other fluid flow conduit to additional scavengerair supply and exhaust flow paths and to additional enclosed spacesupply and return flow paths.

Moreover, example systems in accordance with this disclosure can beemployed in combination with other heating, cooling,humidification/dehumidification, recovery, regeneration and othercomponents or systems located within or otherwise along these additionalscavenger and process air flow paths.

The process plenum 205 can be configured to provide air cooling to thehot aisle return air using the reduced-temperature water or coolingfluid from the tank 222. A liquid-to air heat exchanger, LAHX 217 can bearranged inside the process plenum 205 and can be configured to providecooling to the hot aisle return air. The LAHX 217 can directly andsensibly cool the air from the enclosed space using water cooled in theevaporative cooler 210 (or in the recovery coil 212 in an economizermode).

The dry coil or recovery coil 212, arranged inside the scavenger plenum204, can also be a LAHX. Both the LAHX 217 and the recovery coil 212 caninclude a variety of kinds of liquid-to-air exchangers, including, forexample, cooling coils. Cooling coils are commonly formed of coiledcopper tubes embedded in a matrix of fins. A variety of particularconfigurations, capacities, etc. can be employed in examples accordingto this disclosure. Other example LAHXs that can be used includemicro-channel heat exchangers. The cooling fluid circulating through oneor both of LAHX 217 and the recovery coil 212 can include water, liquiddesiccant, glycol, other hygroscopic fluids, other evaporative liquids,and/or combinations thereof. In an example, the cooling fluid flowingthrough the LAI-IX 217 and the recovery coil 212 can be the coolingfluid (for example, water) flowing through the evaporative cooler 210.In another example, the cooling fluid flowing through one or both of theLAHX 217 and the recovery coil 212 can be the same as or different thanthe cooling fluid flowing through the evaporative cooler 210.

The conditioning system 200 can include a process fan (or fan array) 215which can be similar to the scavenger fan (or fan array) 214 and candrive the process air through the process plenum 205. Exampleconditioning system 200 and other example conditioning systems hereincan include additional fans than what is shown in the figures. Moreover,the fans can be located in different locations within the system 200relative to what is shown in FIG. 2. For example, one or both of thescavenger fan 214 and the process fan 215 can be configured as a singlefan or multiple fans, including a fan array, such as, for example,FANWALL® Systems provided by Nortek Air Solutions. Although not shown inthe figures, example conditioning systems in accordance with thisdisclosure can include one or more filters disposed in one or both ofthe scavenger plenum 204 and the process plenum 205.

In the examples of FIGS. 1A, 1B and 2, the scavenger fan 114/214 can bearranged inside the scavenger plenum 104/204 downstream of the recoverycoil 112/212. In this position, at least some of the heat generated bythe scavenger fan 114/214 can be exhausted out of the scavenger plenum104/204 through the scavenger outlet 108/208, which is just downstreamof scavenger fan 114/214. In other examples, the scavenger fan 114/214can be located at different positions within scavenger plenum 104/204.In the example of FIG. 2, the process fan 215 can be arranged inside theprocess plenum 205 upstream of the LAHX 217. In this position, some heatgenerated by the process fan 215 can be directly removed by the LAHX 217before the air is supplied back to the space. In other examples, theprocess fan 215 can be located at different positions within the processplenum 205.

Similar to the conditioning system 100A, the tank 222 in theconditioning system 200 can include two output lines and correspondingpumps. A pump 272 can pump water from the tank 222 to the pre-cooler 260through a water line 274. Instead of pumping water from the tank 222 tothe data center or cold water main, as described above in reference toFIG. 1A, a pump 224 can pump water from the tank 222 through a waterline 225 to the LAHX 217 in the process air plenum 205. As such, thereduced-temperature water from the tank 222 can provide cooling (via theLAHX 217) to the process air flowing through the process air plenum 205.In other examples, one water line and one pump can be used to deliverwater out of the tank 222 and a split valve can be used to control thedelivery of water to the LAHX 217 and to the pre-cooler 260.

As provided above, in the LAHX 217 the reduced-temperature water fromthe evaporative cooler 210 and recovery coil 212 can cool the hotprocess air in the process plenum 205. Thus the water exiting the LAHX217 can be at a higher temperature relative to a temperature at an inletof the LAHX 217. The increased-temperature water exiting the LAHX 217can flow back to the recovery coil 212 via a water line 219 to cool thewater before it returns to the evaporative cooler 210 or the tank 222.

Although not shown in FIG. 2, the tank 222 can include a make-up valveand a drain valve to maintain the fluid level and hardness level insidethe tank 222. The tank 222 can include one or more temperature sensorsin or around the tank to monitor a temperature of the fluid storedtherein. In an example, the control scheme for conditioning system 200can be based, in part, on a measured temperature of the fluid in tank222 compared to a set point temperature. In an example, the set pointtemperature can be pre-determined based on an estimated cooling loadfrom the enclosed space. The set point water temperature can also varyduring operation of conditioning system 200, based in part on conditionsin the enclosed space (for example, operation of the data center likeperiodic processing load variations).

The conditioning system 200 can allow for multiple operating modes andselection of the mode can depend, in part, on the outdoor air conditionsand a cooling load for the system 200. Because the type and arrangementof the components in the scavenger plenum 204 is similar to the type andarrangement of the components in the scavenger plenum 104A of FIG. 1A,the conditioning system 200 can operate similar to the conditioningsystem 100A and the three operating modes for the conditioning system200 can be generally similar to the modes as described above inreference to FIG. 1A. In an example, the evaporative cooler 210 canoperate adiabatically with a closed evaporative fluid circuit, as alsodescribed above under FIG. 1B; thus providing additional modes ofoperation for the conditioning system 200. The conditioning system 200can include a system controller 248 that can be similar to the systemcontroller 148A of FIG. 1A and described above.

Reference is made to International Application No. PCT/CA2016/050507,filed on May 2, 2016, which is incorporated by reference herein andprovides further examples of air cooling applications that can utilizethe methods and systems disclosed herein.

Similar to the system 100A of FIG. 1A, the cooling fluid circuit of thepre-cooler 260 can be referred to herein as a coupled design. First, thecooling fluid for the pre-cooler 260 comes from the water in the tank222, which is produced by the evaporative cooler 210. Second, the fluidat an outlet of the pre-cooler 260 is directed to and flows through theevaporative cooler 210. In other examples, the cooling fluid circuit ofthe pre-cooler 260 can be decoupled from the evaporative cooler 210.

FIG. 3 illustrates an example conditioning system 300 for providingliquid cooling to a heat load. The conditioning system 300 can include ascavenger plenum 304, which can also be a housing or system cabinet. Thescavenger plenum 304 can include the same main components arrangedinside the plenums 104A or 104B of FIGS. 1A and 1B, and described abovein reference to the conditioning systems 100A and 100B. For simplicity,some features and details of the conditioning system 300 are notspecifically shown in FIG. 3. For example, although FIG. 3 excludes afan (like fan 114A of FIG. 1A), it is recognized that a fan can beincluded in the system 300. Dampers are not shown in FIG. 3 at the inletor outlet of the plenum, or at the bypass locations (see dampers 176Aand 134A in FIG. 1A). However, it is recognized that any or all of suchdampers can be included in the system 300.

Similar to the conditioning system 100A, the conditioning system 300 canbe configured to produce reduced-temperature water that can be used forliquid cooling for a heat load. The plenum 304 can also be referred toas the cooling system or cooling unit 304 since it houses the componentsconfigured to provide liquid cooling to the heat load. The plenum 304can include a pre-cooler 360, an evaporative cooler 310 and a recoverycoil or dry coil 312, similar to the plenum 104A. FIG. 3 illustrates adesign for the conditioning system 300 in which the pre-cooler 360 canbe partially decoupled from the evaporative cooler 310 and recovery coil312, as described further below.

Reduced-temperature water (or other cooling fluid) from the cooling unit304 can be supplied to the heat load, as represented in FIG. 3 as a coldwater supply 340. The reduced-temperature water can be stored in a tank322 and delivered to the cold water supply 340 via a water line 339. Inan example, the cold water supply 340 can be a cold water lineconfigured to transport the water from the tank 322 to the heat load. Inan example, the cold water supply 340 can be a cold water manifold thatcan receive water from more than one scavenger plenum or cooling unit304 within the conditioning system 300, as described below in referenceto FIG. 4. The cold water supply 340 can be part of a process coolingfluid supply circuit that provides the cold water (or other processcooling fluid) to the heat load. The heat load can receive the coldwater/process cooling fluid from the supply 340 and thereby reject heat;such heat can be received by the water/process cooling fluid. Thewater/process cooling fluid can thus be at an increased-temperatureafter providing cooling to the heat load.

The increased-temperature water/process cooling fluid can be returnedfrom the heat load to the scavenger plenum 304, as represented in FIG. 3as a hot water return 342. The hot water return 342 can be part of aprocess cooling fluid return circuit that can return theincreased-temperature water/process cooling fluid to the plenum 304 viaa water line 343 connected to the hot water return 342. The plenum orcooling unit 304 can cool the increased-temperature water/processcooling fluid such that it can again supply cooling to the heat load. Inan example, the hot water return 342 can be a hot water line configuredto transport the increased-temperature water/process cooling fluid fromthe heat load back to the scavenger plenum 304. In an example, the hotwater return 342 can be a hot water manifold that can receivewater/process cooling fluid coming back from the heat load anddistribute the water/process cooling fluid back to more than onescavenger plenum 304 within the conditioning system 300, as describedbelow in reference to FIG. 4.

For simplicity, FIG. 3 does not show a fluid circuit for thewater/process cooling fluid through the recovery coil 312 or theevaporative cooler 310. Moreover, FIG. 3 does not show a fluid pathbetween the recovery coil 312 and evaporative cooler 310. Rather, FIG. 3shows the increased-temperature water in the water line 343 transportedto a dotted-line box designated as 336 for labeling purposes only.

The increased-temperature water from the line 343 can be cooled usingthe recovery coil 312 and the evaporative cooler 310. Similarly, FIG. 3shows the reduced-temperature water leaving the plenum 304 from 336 viaa water line 341 to the tank 322. In an example, the fluid circuits forthe recovery coil 312 and the evaporative cooler 310 can be configuredas shown above in FIG. 1A, including the water line 130A and bypassvalve 132A. In an example, the fluid circuits can be configured as shownbelow in FIGS. 1B and 6 in which separate tanks or tank sections can beused to control the flow of water to and from the evaporative cooler 310and recovery coil 312. In an example, the evaporative cooler 310 andrecovery coil 312 can be fluidly disconnected such that thereduced-temperature water in the recovery coil 312 does not pass throughthe evaporative cooler 310. In some cases, such fluid disconnection canbe selective and under particular air conditions or operating modes whenan adiabatic process is used. In other cases, the evaporative cooler 310can be configured such that the fluid flow path through the evaporativecooler 310 can essentially always be separate from the fluid flow paththrough the recovery coil 312 (see, for example, FIG. 11).

The conditioning system 300 can be controlled in a similar manner asdescribed above for the conditioning systems 100A and 100B of FIGS. 1Aand 1B, respectively. The conditioning system 300 can operate in themultiple modes described above for the conditioning systems 100A and100B of FIGS. 1A and 1B, respectively.

In an example, as shown in FIG. 3, the pre-cooler 360 can be partiallydecoupled from the evaporative cooler 310 and the recovery coil 312.Instead of receiving water directly from the tank 322 (see FIG. 1A), thepre-cooler 360 can receive water from the cold water supply 340 via awater line 344 and use the water from cold water supply 340 as thecooling fluid for the pre-cooler 360. Instead of transporting the waterexiting the pre-cooler 360 directly to the evaporative cooler 310 (seeFIG. 1A), the water exiting the pre-cooler 360 can be delivered to thehot water return 342 via a water line 346. In this partially decoupleddesign, the pre-cooler 360 can have a fluid circuit, which includes thewater lines 344 and 346, separate from a fluid circuit for theevaporative cooler 310 and the recovery coil 312. The pre-cooler 360 canbe referred to herein as partially decoupled (rather than whollydecoupled) because the pre-cooler 360 can use reduced-temperature waterproduced by the evaporative cooler 310 or recovery coil 312, but thepre-cooler 360 can receive the reduced-temperature water from the coldwater supply 340, rather than directly from the tank 322. Second, thepre-cooler 360 can be referred to herein as partially decoupled (ratherthan wholly decoupled) because the water exiting the pre-cooler 360 canbe transported to the hot water return 342, rather than directly back tothe evaporative cooler 310 (see FIG. 1A) or to one of two tanks (seeFIG. 1B). The water in the hot water return 342 can be circulated backto the recovery coil 312.

In the partially decoupled design of FIG. 3, the fluid circuit for thepre-cooler 360 can be separate from the fluid circuits for theevaporative cooler 310 and the recovery coil 312. This can simplifyfluid circuity in the plenum 304, to the evaporative cooler 310, or tothe recovery coil 312. Moreover, the pre-cooler 360 can be an optionalcomponent of the conditioning system 300 that can be excluded in someapplications, depending, for example, on climate. By decoupling thefluid path of the pre-cooler 360 from the other fluid paths through theevaporative cooler 310 and recovery coil 312, it can be easier toinclude or exclude the pre-cooler 360 in designing a conditioning systemfor a particular climate and cooling load. Additional benefits of thepartially decoupled design of FIG. 3 are described further below inreference to FIG. 4.

FIG. 4 illustrates an example conditioning system 400 which includesmultiple cooling units 404 (designated as 404A, 404B, and 404C) arrangedin parallel. Each cooling unit 404 can be configured similarly to thescavenger plenum 304 and can include the same components, generallyarranged in the same way, inside the cooling unit 404. In the example ofFIG. 4, the evaporative cooler for each of the cooling units 404 can bea liquid to air membrane energy exchanger (LAMEE) 411, which is oneexample of the type of evaporative cooler usable in the conditioningsystems described herein. The LAMEE 411 is described in further detailbelow.

Each cooling unit 404 can produce reduced-temperature water that can beprovided to a cold water supply 440 to provide liquid cooling to a heatload. In an example, and as shown in FIG. 4, the heat load can be a datacenter or other enclosed space having one or more heat generatingcomponents. In other examples, the heat load can be from one or moredevices not contained within an enclosed space and open to theatmosphere. The cold water supply 440 can be part of a process coolingfluid supply circuit and can be fluidly connected to each of the coolingunits 404A, 404B and 404C via water lines 441A, 441B and 441C,respectively. Although FIG. 4 does not show any tanks for the coolingunits 404, it is recognized that one or more tanks can be included foreach cooling unit 404A, 404B, 404C for receiving the water from theLAMEE 411 and recovery coil 412 and transporting the water to the coldwater supply 440. Alternatively, a tank can be fluidly connected to morethan one of cooling units 404.

After the water has provided liquid cooling to the data center (heatload), the water can be transported back to the cooling units 404through the hot water return 442. The hot water return 442 can be partof a process cooling return circuit and can be fluidly connected to adry coil or recovery coil (RC) 412 of each of the cooling units 404A,404B and 404C via water lines 443A, 443B and 443C, respectively.

As described above in FIG. 3, for simplicity, the fluid circuits of theLAMEE 411 and recovery coil 412 are not shown in FIG. 4 for each of thecooling units 404A, 404B and 404C. Rather, the water lines 443A, 443Band 443C are shown connected to 436 around both the evaporative cooler410 and recovery coil for each of the cooling units 404A, 404B and 404Cand connected to the hot water return 442; similarly, the water lines441A, 441B and 441C are shown between 436 and the cold water supply 440.

As similarly described above for the conditioning system 300,pre-coolers 460 of each of the cooling units 404A, 404B and 404C can bepartially decoupled from the other components (LAMEE 411 and recoverycoil 412) of the respective cooling unit 404. Each pre-cooler 460 canreceive cold water from the cold water supply 440 via water lines 444A,444B and 444C. After passing through the pre-cooler 460 of each coolingunit 404A, 404B and 404C, the water can be transported to the hot waterreturn via water lines 446A, 446B and 446C.

In the example of FIG. 4, the conditioning system 400 can include threecooling units 404. It is recognized that more or less cooling units 404can be included in the conditioning systems described herein. Any numberof cooling units can be used in parallel. The number of cooling units404 can depend on a cooling capacity of each unit 404 and the heat loadof the data center or other enclosed space. As provided above in thedescription of FIG. 3, a pre-cooler having a partially decoupled coolingcircuit can provide advantages over a coupled pre-cooler design. Whenthe pre-cooler 460 is not needed, the entire flow rate of cold waterproduced by the LAMEE 411 and recovery coil 412 can be delivered to theheat load via the cold water supply 440. This can maximize availablecooling power that can be delivered to the heat load during a majorityof the operating time of the conditioning system 400 (when thepre-cooler 460 of each unit 404 is not needed). This can also provideflexibility to the conditioning system 400 in that individual units 404can be cycled on and off depending on outdoor air conditions and demandsof the heat load.

Moreover, with the design shown in FIG. 4, a gross cooling capacity ofeach unit 404 (i.e. the total cooling produced by the LAMEE 411 andrecovery coil 412) can be a standard value given by the design of thesystem 400, which can include the maximum water flow rate through eachunit 404 and a peak capacity of the recovery coil 412 and LAMEE 411. Inany given cooling application, a ratio of cooling allocated to thepre-cooler 460 can be varied depending in part on climate conditions andrequirements from the heat load. When the pre-coolers 460 are not beingrun, a flow rate through the units 404 can be reduced and all of theunits 404 can remain running, or the maximum water flow rate can bemaintained and some units 404 can be shut down. The partially decoupledpre-cooler layout of FIG. 4 provides flexibility in configuring eachcooling unit 404 and thus the conditioning system 400 for differentcooling applications. Reference is made to Table 4 below for a modeledconditioning system having a plurality of process cooling units with apartially decoupled pre-cooler design similar to that shown in FIG. 4.

As provided above and shown in FIG. 4, some or all of the cooling units404 can include a LAMEE 411 as the evaporative cooler in the coolingunits 404. The LAMEE 411 can also be referred to herein as an exchangeror an evaporative cooler LAMEE. A liquid to air membrane energyexchanger (LAMEE) can be used as part of a heating and cooling system(or energy exchange system) to transfer heat and moisture between aliquid desiccant and an air stream to condition the temperature andhumidity of the air flowing through the LAMEE.

In an example, the membrane in the LAMEE 411 can be a non-porous filmhaving selective permeability for water, but not for other constituentsthat form the liquid desiccant. Many different types of liquiddesiccants can be used in combination with the non-porous membrane,including, for example, glycols. The non-porous membrane can make itfeasible to use desiccants, such as glycols, that had been previouslydetermined to be unacceptable or undesirable in these types ofapplications. In an example, the membrane in the LAMEE can besemi-permeable or vapor permeable, and generally anything in a gas phasecan pass through the membrane and generally anything in a liquid phasecannot pass through the membrane. In an example, the membrane in theLAMEE can be micro-porous such that one or more gases can pass throughthe membrane. In an example, the membrane can be a selectively-permeablemembrane such that some constituents, but not others, can pass throughthe membrane. It is recognized that the LAMEEs included in theconditioning systems disclosed herein can use any type of membranesuitable for use with an evaporative cooler LAMEE.

In an example, the LAMEE or exchanger 411 can use a flexible polymermembrane, which is vapor permeable, to separate air and water. The waterflow rate through the LAMEE 411 may not be limited by concerns ofcarryover of water droplets in the air stream, compared to otherconditioning systems. The LAMEE 411 can operate with water entering theLAMEE 411 at high temperatures and high flow rates, and can therefore beused to reject large amounts of heat from the water flow using latentheat release (evaporation).

The cooling fluid circulating through the LAMEE or exchanger 411 caninclude water, liquid desiccant, glycol, other hygroscopic fluids, otherevaporative liquids, and/or combinations thereof. In an example, thecooling fluid is a liquid desiccant that is a low concentration saltsolution. The presence of salt can sanitize the cooling fluid to preventmicrobial growth. In addition, the desiccant salt can affect the vaporpressure of the solution and allow the cooling fluid to either releaseor absorb moisture from the air. The concentration of the liquiddesiccant can be adjusted for control purposes to control the amount ofcooling of the scavenger air or cooling fluid within the LAMEE orexchanger 411.

Using a LAMEE in the cooling units 404 can offer advantages overconventional cooling systems, such as cooling towers, for example. Themembrane separation layer in the LAMEE can reduce maintenance, caneliminate the requirement for chemical treatments, and can reduce thepotential for contaminant transfer to the liquid loop. The use of LAMEEsalong with an upstream or downstream cooling coil can result in a lowertemperature of the water leaving the LAMEE and a higher coolingpotential. Various configurations of cooling systems having a LAMEE canboost performance in many climates. Higher cooling potential andperformance can result in lower air flow and fan power consumption inthe cooling system, which is the main source of energy consumption inliquid-cooling systems, and can increase the overall data center coolingsystem efficiency.

The cooling units 404, which can each include the LAMEE 411, can besmaller in size relative to conventional cooling systems, such as acooling tower having a similar cooling capacity. The cooling units 404can require less water treatment and water filtration compared toconventional cooling systems since the water and the scavenger air inthe LAMEE 411 do not come into direct contact with each other.

In the exemplary system 400 of FIG. 4, the LAMEE 411 can be configuredto receive the water exiting the recovery coil 412 such that the watercan circulate through the LAMEE 411 for further cooling, prior to beingtransported to the cold water supply 440. Under some conditions, theLAMEE 411 can be configured to operate adiabatically such that the fluidflow path through the LAMEE 411 can be selectively disconnected from thefluid flow path in the recovery coil 412. Each of these scenarios aredescribed above for an evaporative cooler in reference to and as shownin FIGS. 1A and 1B.

It is recognized that a LAMEE can be used in the other conditioningsystems which are described as including an evaporative cooler, and theLAMEE can provide the features and benefits described above in referenceto the LAMEE 411 of FIG. 4.

In another example, as an alternative to a LAMEE, some or all of thecooling units 404 can include a cooling tower including one or moreevaporative coolers. A cooling tower including an associated evaporativecooler can also be used in any of the other conditioning systemsdescribed herein.

FIG. 5 illustrates an example conditioning system 500, having a coolingunit (or scavenger air plenum) 504 having an inlet 506 and an outlet508. The cooling unit 504 can include a pre-cooler 560, a LAMEE 511, adry coil or recovery coil 512, and a fan 514, all of which can bearranged inside the cooling unit 504.

The cooling unit 504 can generally operate similar to the cooling unitsdescribed above to produce cold water that can be temporarily stored ina tank 522 and then delivered to a heat load 502, as cold water supply,to provide liquid cooling. The cold water supply can be part of aprocess cooling fluid supply circuit. The increased-temperature waterexiting the heat load 502 can then be returned to the recovery coil 512,as hot water return, for recirculation. The hot water return can be partof a process cooling fluid return circuit. The cooling unit 504 canoperate in the multiple modes of operation described above in referenceto the conditioning system 100A of FIGS. 1A. A bypass valve 532 cancontrol a distribution of the water from the recovery coil 512,depending on the operating mode.

The pre-cooler 560, as shown in the example of FIG. 5, can have anexternal cooling circuit 550. For purposes herein, the cooling circuit550 for the pre-cooler 560 is described as being an external coolingcircuit when the cooling fluid for the pre-cooler 560 is decoupled fromthe process water circuit of reduced-temperature water produced by theLAMEE 511 or recovery coil 512. In other words, the cooling circuit 550for the pre-cooler 560 can be wholly or fully separate from the fluidcircuit flowing through the LAMEE 511 or recovery coil 512, whichprovide liquid cooling to the heat load 502.

The external cooling circuit 550 for the pre-cooler 560 can allow theexchanger or LAMEE 511 to develop a higher cooling capacity in theprocess water circuit, which can significantly improve the cost per kWof the conditioning system 500. In other words, essentially the entiregross cooling capacity of the LAMEE 511 and recovery coil 512 can go tothe heat load. As provided below, the external cooling circuit 550 caninclude a low-cost fluid cooler, such as, for example, an open coolingtower, which can be used only when needed by the load of the pre-cooler560. In an example, the pre-cooler 560 can be an optional add-on to theconditioning system 500 depending on application or climate conditions,and the pre-cooler 560 can be sized accordingly. The gross coolingcapacity of the cooling unit 504 can be potentially twice as much as thenet cooling capacity of a cooling unit similar to the cooling system104A of FIG. 1A which has a coupled pre-cooler 160A. In an example inwhich multiple cooling units 504 are used to provide cooling to the heatload 502, a reduced number of cooling units can be used to achieve thesame amount of cooling. This can reduce the overall footprint of thecollective units and can markedly improve the cost-effectiveness andprofitability of the conditioning system.

The fluid circuit 550 for the pre-cooler 560 can include a fluid cooler552 through which the cooling fluid can pass after the cooling fluidexits the pre-cooler 560. The fluid cooler 552 can reduce a temperatureof the cooling fluid, at which point the cooling fluid can then berecirculated through the pre-cooler 560 in order to continue cooling theoutdoor or scavenger air passing through the plenum 504.

The fluid cooler 552 of FIG. 5 can be any type of cooling deviceconfigured to reduce a temperature of the cooling fluid passing therethrough. In an example, the fluid cooler 552 of FIG. 5 can include butis not limited to a liquid to liquid heat exchanger, a refrigerant toliquid exchanger (such as an evaporator in a mechanical cooling system),an adiabatic or other type of evaporative fluid cooler, a cooling tower(closed or open circuit), or a combination thereof.

In an example, the fluid cooler 552 can be external to the cooling unit504 and can be physically separate from the cooling unit/plenum 504containing the LAMEE 511 and other components. In an example, the fluidcooler 552 can be housed within the cooling unit/plenum 504 containingthe LAMEE 511 and other components.

Primarily for purposes of distinction and clarity, the cooling unit 504can be referred to herein as a process cooling unit and the fluid cooler552 can be referred to herein as an auxiliary cooling unit. Thisterminology can also be applicable to the conditioning systems in FIGS.6-10. The auxiliary cooling unit (i.e. fluid cooler 552) can receive theincreased-temperature water exiting the pre-cooling coil 560 from theprocess cooling unit (i.e. cooling unit 504). The auxiliary cooling unit552 can reduce a temperature of the water and then recirculate the waterback through the pre-cooling coil 560 of the process cooling unit 504.The fluid cooler 552 can be used during operation of the cooling unit504 in an enhanced mode in which the pre-cooler 560 can be used tocondition the scavenger air prior to passing the scavenger air throughthe LAMEE 511. In other modes, the pre-cooler 560 can be bypassed orturned off, in which case the fluid cooler or auxiliary cooling unit 552is not running.

FIG. 6 illustrates another example conditioning system 600 having acooling unit 604 (process cooling unit), which can be configuredsimilarly to the conditioning system 500 and include an external coolingcircuit 650 for a pre-cooler 660 of the cooling unit 604. The externalcooling circuit 650 can be separate or decoupled from a fluid circuitfor the process water used for liquid cooling of a heat load 602. Theexternal cooling circuit 650 can include a fluid cooler 652, alsoreferred to as an auxiliary cooling unit 652, configured to providecooling for the cooling fluid in the pre-cooler 660.

The cooling unit 604 can operate generally similar to the cooling unit504 of FIG. 5 and can include the pre-cooler 660, a LAMEE 611, a drycoil or recovery coil 612 and a fan 614. The conditioning system 600 ofFIG. 6 is included herein to illustrate an example of a type of fluidcooler that can be used in the external cooling circuit 650. Suchexemplary fluid cooler 652 can include a LAMEE and is described furtherbelow. It is recognized that any type of fluid cooler can be used in theauxiliary cooling unit 652.

The configuration of the LAMEE 611 and the recovery coil 612 can beconfigured similar to the design of the evaporative cooler 110B and therecovery coil 11B of FIG. 1B. The system 600 can include a first tank622 and a second tank 623 for the LAMEE 611 and the recovery coil 612.In an example, the first tank 622 and second tank 623 can be connectedto each other but can have a partition 633 or other type of separationbetween them. In an example, the partition 633 can be configured suchthat it can be lowered to reduce a height of the partition 633 duringoperation in the evaporation mode (as described above in reference toFIG. 1B). The partition 633 can function similar to a weir between thetanks 622 and 623 such that when the partition 633 is lowered, the watercan spill over the partition if the level gets too high in one of thetanks In another example, as shown in FIG. 1B, the two tanks 622 and 623can be separate tanks disconnected from one another with an equalizationvalve there between.

The fluid circuits for the LAMEE 611 and the recovery coil 612 can besimilar to those shown in FIG. 1B and described in detail above. Thusthe water lines and valves for the LAMEE 611 and recovery coil 612 arenot labeled in FIG. 6 or described in detail for the system 600. TheLAMEE 611 can operate adiabatically as described above in reference tothe evaporative cooler 110B of FIG. 1B. The cooling unit 604 can operatein the multiple modes described above in reference to the system 100B ofFIG. 1B. However, in contrast to FIG. 1B, the conditioning system 600 ofFIG. 6 can have the decoupled pre-cooler 660 design. The fluid cooler orauxiliary cooling unit 652 can provide the cooling fluid to thedecoupled pre-cooler 660.

In the example of FIG. 6, the fluid cooler or auxiliary cooling unit 652can include a LAMEE 662, a recovery coil 664, and a fan 666 arranged ina scavenger air plenum 653 and configured to reduce a temperature of thecooling fluid from the pre-cooler 660. The scavenger air plenum 653 caninclude an inlet 655 configured to receive an outdoor air stream suchthat the outdoor or scavenger air flows through the plenum 653 and outof the plenum 653 via an outlet 657. The LAMEE 662 can condition thescavenger air flowing there through such that the scavenger air canreduce a temperature of the cooling fluid passing through the recoverycoil 664.

In the example, as shown in FIG. 6, the auxiliary cooling unit 652 canoperate similar to the systems 100A or 100B, with the exception that theauxiliary cooling unit 652 as shown in FIG. 6 excludes a pre-cooler. Asit is shown in FIG. 6, the auxiliary cooling unit 652 can be configuredto operate in multiple modes (excluding the super-evaporation mode),including economizer, adiabatic and evaporation modes. However, in someexamples, the design of the auxiliary cooling unit 652 can be simplifiedand may not include the capability to operate in multiple operatingmodes. It is recognized that it is not practical to run the auxiliarycooling unit 652 in an economizer mode. In most cases, the auxiliarycooling unit 652 can be operational during high ambient conditions sinceit is running when the pre-cooler 660 of the process unit 604 isrunning. As such, the auxiliary cooling unit 652 can be configured foran evaporation mode, similar to the description above under FIG. 1B, andin some cases, the auxiliary cooling unit 652 can be configured forselectively operating in an adiabatic mode.

In an example, the water lines to and from the LAMEE 662 and therecovery coil 664 can be similar to those shown in FIG. 6 for the LAMEE611 and recovery coil 612, both of the process cooling unit 604, orsimilar to those shown in FIG. 1B for the evaporative cooler 110B andthe recovery coil 112B. In an example, the auxiliary cooling unit 652can include a first tank 668 and a second tank 669.

The external cooling circuit 650 can include a water line 651 fluidlyconnected to an outlet of the pre-cooler 660 and an inlet of therecovery coil 664. As such, the increased-temperature fluid exiting thepre-cooler 660 can be delivered to the auxiliary cooling unit 652. Theincreased-temperature fluid can pass through the recovery coil 664 atwhich point the conditioned air exiting the LAMEE 662 can be used toreduce a temperature of the cooling fluid in the recovery coil 664. Thereduced-temperature fluid can then be delivered to at least one of thefirst tank 668 and the second tank 669. The cooling fluid in the tank669 can be circulated through the LAMEE 611 and then delivered to atleast one of the first tank 668 and the second tank 669.

FIG. 6 includes the control valves for the distribution of the coolingfluid among the tanks 668 and 669 (similar to the valves 132B and 182Bdescribed above in reference to the system 100B of FIG. 1B); however, itis recognized that the control valves in FIG. 6 can be excludeddepending on whether the unit 652 is configured for multiple operatingmodes. A pump 670 can deliver the fluid from the tank 668 back to thepre-cooler 660 of the process cooling unit 604 via a water line 671,which can be part of the external cooling circuit 650.

As it is shown in FIG. 6, the auxiliary cooling unit 652 can include theLAMEE 662 and recovery coil 664 in combination. In another example, tosimplify a design of the unit 652, the recovery coil 664 can be excludedfrom the unit 652 and the LAMEE 662 can operate essentially alone toreduce a temperature of the cooling fluid from the pre-cooler 660.

As described above in reference to the conditioning system 500, theauxiliary cooling unit 652 can be used when the process cooling unit 604is operating in an enhanced mode in which the pre-cooler 660 can be usedto pre-condition the scavenger air entering the cooling unit 604. In theeconomizer and evaporation modes for the process cooling unit 604, thepre-cooler 660 can be bypassed or turned off, in which case theauxiliary cooling unit 652 can be inactive or turned off. The processcooling unit 604 can be operated in an adiabatic mode for the LAMEE 611with the pre-cooler 660 turned on. In this hybrid mode (as it isreferred to above in reference to FIG. 1B), the auxiliary cooling unit652 can be active since the pre-cooler 660 is being used in the processcooling unit 604.

The auxiliary cooling unit 652 can serve more than one process coolingunit. As shown in FIG. 6, the water line 651 can include a junction 684or common return line that can receive increased temperature fluids frommultiple pre-coolers of multiple process cooling units. Similarly, thereduced temperature fluid exiting the auxiliary cooling unit 652 via theline 671 can be delivered back to more than one process cooling unit.The line 671 can include a junction 686 or common supply line fordistributing the reduced temperature fluid back to multiple processcooling units, including the process cooling unit 504 of FIG. 6. In anexample, each of junctions 684 and 686 can represent a manifold. In suchan example, the various outlets of the pre-coolers (from the processcooling units) can be hooked in parallel with one another and connectedvia a manifold pipeline that can deliver the increased temperature waterfrom each process cooling unit to the recovery coil 664 of the auxiliarycooling unit 652. Similarly, the outlet of the water tank 668 of theauxiliary cooling unit 652 can be fluidly connected to a manifold todistribute the reduced temperature water from the auxiliary cooling unit652 to the inlet of the pre-cooler for each of the process coolingunits. This is further illustrated in an example conditioning systemshown in FIG. 9 and described below.

In another example, the auxiliary cooling unit 652 can include apre-cooler upstream of the LAMEE 662, in which case the unit 652 canoperate similar to the systems 100A and 100B of FIGS. 1A and 1B,respectively, and can include an enhanced mode of operation. In such anexample, the pre-cooler can have a coupled or a decoupled coolingcircuit. In the example in which the pre-cooler of the auxiliary coolingunit 652 has a decoupled cooling circuit, the cooling fluid used in thepre-cooler could be cooled by another auxiliary cooling unit, whichsimilarly could have a pre-cooler cooled by yet another auxiliarycooling unit and so on. These stages of auxiliary cooling units can usevarious types of evaporative coolers in addition to or as an alternativeto a LAMEE.

With regard to FIGS. 5 and 6, typically the auxiliary cooling unit 552or 652 can run at higher water temperatures compared to the processwater circuit of the process cooling unit 504 or 604. As such, in anexample in which the auxiliary cooling unit includes a LAMEE (forexample, LAMEE 511 or 611), a pre-cooler may not be needed in theauxiliary cooling unit 552 or 652 to reach sufficiently cooltemperatures for the cooling fluid for the pre-coolers 560 and 660 ofthe process cooling units 504 and 604, respectively. Because of thehigher operating temperatures of the auxiliary cooling units 552 and652, the auxiliary cooling units 552 and 652 can develop even highercooling capacities for the same size unit.

In an example, one auxiliary cooling unit can be dedicated to oneprocess cooling unit. In an example, an auxiliary cooling unit can be amodule attached externally (on top or on the side or end) of the processcooling unit, or the auxiliary cooling unit can be a separate unitconnected with water piping to the process cooling unit.

The decoupled pre-cooler circuits 550 and 650 of FIGS. 5 and 6 canimprove the control characteristics of the process cooling units 504 and604 in the enhanced or super-evaporative mode of the process coolingunits 504 and 604. In a coupled design in which the pre-cooler uses thereduced temperature water (or process water) from the evaporative coolerand recovery coil (see, for example, FIG. 1A), the system capacity canpeak at less than the maximum scavenger air flow rate, and thus wouldnot increase further with additional air flow. For example, the systemcapacity could peak at about ⅔ to ¾ of the maximum scavenger air flowrate. This is a result of the pre-cooler or pre-cooling coil in the unit504 or 604 continuing to increase its heat load, and such heat loadneeds to be rejected by the evaporative cooler (LAMEE 511 or 611), withno net cooling benefit to the process water circuit. With the de-coupledpre-cooler 560 and 660 shown in FIGS. 5 and 6, respectively, anddescribed herein, the LAMEE 511 or 611 can develop all of its coolingpower potential in the process water flow up to the maximum scavengerair flow rate. In other words, through the design of a decoupledpre-cooler, the scavenger air flow rates through the process coolingunits 504 or 604 can be increased up to the peak flow rate capacity ofthe LAMEE 511 or 611. This can support an increased cooling power of theprocess cooling units 504 or 604.

The tables below illustrate the performance for a modeled cooling orconditioning system as an example having a plurality of process coolingunits and a plurality of auxiliary cooling units, which can be similarto those shown in the conditioning system 600 of FIG. 6. FIG. 7 depictsone process cooling unit for this exemplary system as a process coolingunit 704. FIG. 8 depicts one auxiliary cooling unit for this exemplarysystem as an auxiliary cooling unit 752. A system controller 748 isshown in FIGS. 7 and 8 and can be included in the conditioning systemfor controlling operation of the process cooling units 704 and auxiliarycooling units 752.

The modeled cooling or conditioning system can be configured to providecooling to a data center 702 with a cooling load of 5 megawatts. Thedata for the process cooling units 704 is shown in Table 1 below. Inthis example, a set point temperature for the cold process waterproduced by the cooling unit 704 (for the data center 702) can be set at80 degrees Fahrenheit —this is referred to below in Table 1 as the“Cooling Coil water inlet set point.” (The set point temperature canvary depending on the application and other factors.)

TABLE 1 5 MW Data Center 95FDB/78FWB Outdoor Air Conditions 80 F. EWT,18 F. Delta Sea Level Process Cooling Units - 12 Units (See FIG. 7) FlowRate Pre-cooling coil 760 60 GPM Recovery coil 712 160 GPM LAMEE711 160GPM Airflow (through plenum) 30,000 SCFM Pre-cooler LAMEE Recovery F. C.F. C. F. C. DB in 95 35.0 85 29.4 87.1 30.6 WB in 78 25.6 75.4 24.1 83.328.5 Tw in 81.1 27.3 93.7 34.3 98.0 36.7 DB out 85 29.4 87.1 30.6 97.336.3 WB out 75.4 24.1 83.3 28.5 85.5 29.7 Tw out 91.8 33.2 80.0 26.793.7 34.3 ACFM 31766 31207 31380 F. C. LAMEE water inlet 93.7 34.3Cooling Coil water inlet set point 80 26.7 Water Properties at 32 C. Rho995 kg/m{circumflex over ( )}3 Cp 4.1795 kJ/kgK Total Cooling per Unit420.1 kW

The cooling fluid exiting the pre-cooler 760 of each of the twelve (12)process units 704 can be transported to an auxiliary cooling unit (via asupply circuit 751) and then recirculated back through the pre-cooler760 (via a return circuit 771). Each process cooling unit 704 canprovide 420 kW of cooling to the data center 702.

At a flow rate of 160 gallons per minute and 12 units, the data centeris receiving the cold water at a total flow rate of 1920 gallons perminute. This is the flow rate for which sufficient cold water issupplied to the data center to meet the 5 MW cooling load.

In this example, five (5) auxiliary cooling units 752 can be used incombination with the twelve (12) process cooling units 704. The data forthe auxiliary cooling units 752 is shown in Table 2 below.

TABLE 2 Auxiliary Cooling Units - 5 Units (See FIG. 8) Flow RateRecovery coil 764 144 GPM LAMEE 762 144 GPM Airflow (through 35,000 SCFMplenum) LAMEE Recovery F. C. F. C. DB in 95 35.0 86.9 30.5 WB in 78 25.681.8 27.7 Tw in 89.4 31.9 91.8 33.2 DB out 86.9 30.5 91.3 32.9 WB out81.8 27.7 82.8 28.2 Tw out 80.8 27.1 89.4 31.9 ACFM 37060 36696 F. C.LAMEE water inlet 89.4 31.9 Pre-cooler water inlet 80.8 27.1 WaterProperties at 32 C. Rho 995 kg/m{circumflex over ( )}3 Cp 4.1795 kJ/kgKTotal Cooling per Unit 231.7 kW

As shown in Tables 1 and 2 above, the water exiting the pre-cooler 760of the process cooling unit 704 is at a temperature of 91.8 degreesFahrenheit; the water can enter the recovery coil 764 of the auxiliarycooling unit 752 via a water circuit or line 751 fluidly connected tothe pre-cooler 760 and the recovery coil 764, where it can be reduced to89.4 degrees Fahrenheit. The water can then pass through the LAMEE 762at which point a temperature of the water is reduced to 80.8 degreesFahrenheit. The water at 80.8 degrees Fahrenheit can be returned to theprocess cooling unit (via a water circuit or line 771 fluidly connectedto a tank 768 and the pre-cooler 760) for recirculation through thepre-cooling coil 760 of the process cooling unit 704.

The cooling or conditioning system of FIGS. 7 and 8 can provideapproximately 5040 kW (or 5 megawatts) of cooling since each of thetwelve (12) process cooling units 704 can provide 420 kW of cooling.

The cooling or conditioning system of FIGS. 7 and 8 can be compared to amodeled cooling or conditioning system having a plurality of coolingunits with a similar configuration to the process cooling units of FIG.7 but with a coupled cooling circuit that uses the cold process waterproduced by the unit as the cooling fluid for the pre-cooler coil. Suchsystem can be similar to the conditioning system 100B of FIG. 1B in anexample in which the evaporative cooler 110 is a LAMEE and the systemcan operate at the same outdoor air conditions provided above underTable 1. The data for such process cooling units is provided in Table 3below.

TABLE 3 Comparison for Process Cooling Unit with Coupled Pre-coolersTotal Units: 22 Flow Rate Pre-cooling coil (160) 60 GPM Recovery coil(112) 80 GPM LAMEE (110) 140 GPM Airflow (through plenum) 25,000 SCFMPre-cooler LAMEE Recovery F. C. F. C. F. C. DB in 95 35.0 82.2 27.9 84.529.2 WB in 78 25.6 74.7 23.7 81.7 27.6 Tw in 78.37 25.8 89.8 32.1 98.036.7 DB out 82.2 27.9 84.5 29.2 96.6 35.9 WB out 74.7 23.7 81.7 27.684.4 29.1 Tw out 90.1 32.3 78.4 25.8 89.6 32.0 ACFM 26483 25934 26114 F.C. Mixed LAMEE water inlet 89.81429 32.12 Cooling Coil water inlet setpoint 80 26.67 Water Properties at 32 C. Rho 995 kg/m{circumflex over( )}3 Cp 4.1795 kJ/kgK Total Cooling per Unit 228.9 kW

The set point temperature for delivery to the data center is the same at80 degrees Fahrenheit. Each process cooling unit produces 229 kW ofcooling. As such, in order to produce a comparable amount of totalcooling for the data center (approximately 5000 kW), 22 process coolingunits are needed for the coupled design.

In summary, the modeled cooling system illustrates that 12 processcooling units (each having a decoupled pre-cooler circuit) incombination with 5 auxiliary cooling units (17 units total) can provideequivalent cooling to 22 process units that have a coupled pre-coolerdesign. This reduction in the total number of cooling units, using thedecoupled designs and external cooling described and shown herein, cansignificantly decrease the costs and size of the cooling system for adata center.

Table 4 below shows the data for a modeled conditioning system that canbe similar in configuration to the conditioning system 400 of FIG. 4 andthus can have a partially decoupled pre-cooler design for each of theprocess cooling units. The modeled conditioning system for Table 4 canoperate at the same outdoor air conditions provided above under Table 1.

TABLE 4 Comparison for Process Cooling Unit with Partially DecoupledPre-Coolers (See FIG. 4) Total Units: 17 Flow Rate Pre-cooling coil(460) 37 GPM Recovery coil (412) 150 GPM LAMEE (410) 150 GPM Airflow30,000 SCFM Pre-cooler LAMEE Recovery F. C. F. C. F. C. DB in 95.0 35.087.1 30.6 86.8 30.5 WB in 78.0 25.6 76.0 24.4 82.9 28.3 Tw in 79.9 26.692.8 33.8 97.0 36.1 DB out 87.1 30.6 86.8 30.5 96.3 35.7 WB out 76.024.4 82.9 28.3 85.0 29.4 Tw out 94.0 34.4 79.9 26.6 92.8 33.8 ACFM 3176631207 31380 F. C. Cooling coil return water temperature 98.0 36.7 Mixedreturn water temperature 97.0 36.1 LAMEE water inlet 92.8 33.8 CoolingCoil water inlet set point 80 26.67  Water Properties at 32 C. Rho 995kg/m{circumflex over ( )}3 Cp 4.1795 kJ/kgK Total Cooling per Unit374.27 kW

The set point temperature for delivery to the data center is the same at80 degrees Fahrenheit. Each process cooling unit produces 374 kW ofgross cooling that is provided to the cold water main. However, eachprocess cooling unit draws cold water from the cold water main in orderto direct cold water through the pre-cooler 460 at a flow rate of 37gallons per minute. The flow rate through the recovery coil 412 andLAMEE 411 is at 150 gallons per minute.

At a flow rate of 150 gpm through the LAMEE and recovery coil, 17process cooling units are needed to meet the 5 MW cooling load for thedata center. As provided above under the description in Table 1, to meetthe cooling load, 1920 gallons per minute of cold water is provided tothe data center. Because the pre-coolers of each unit circulates 37gallons per minute of cold water, an additional 629 gallons per minuteof cold water is delivered to the cold water supply or main. Thus atotal of 2550 gallons per minute of cold water is delivered to the coldwater main for both the data center and the pre-coolers.

The water exits the pre-cooler 460 of each unit at a flow rate of 629gpm and at 94 degrees Fahrenheit and is delivered to the hot waterreturn. That water mixes with the water returning from the data centerat a flow rate of 1920 gpm and a temperature of 98 degrees Fahrenheit. Amixing calculation is used to determine that the temperature of thewater in the hot water return is 97 degrees Fahrenheit. That is also theinlet temperature for the recovery coil 412 (see Table 4) since the hotwater from the hot water return is then recirculated back to therecovery coil 412.

FIG. 9 illustrates an example conditioning system 900 having two processcooling units 904A and 904B and one auxiliary unit 952. As shown in FIG.9, the design of the system 900 is similar to the conditioning systemsin FIGS. 6-8 and can include a decoupled fluid circuit for eachpre-cooler 960 in the process cooling units 904 that can be whollyseparate from the process water circuit used to provide liquid coolingto a heat load (for example, a data center or other enclosed space). Thedesign in FIG. 9 shows a process cooling circuit (through each LAMEE 911and RC 912) for multiple cooling units 904, each of which is separatefrom the pre-cooler cooling circuit (or auxiliary cooling circuit).

Each cooling unit 904 can produce reduced-temperature water that can beprovided to a cold water supply 940 to provide liquid cooling to theheat load. The cold water supply 940 can be fluidly connected to each ofthe cooling units 904A and 904B via water lines 941A and 941B. Eventhough FIG. 9 does not show any tanks for the cooling units 904, in anexample, one or two tanks can be fluidly connected and dedicated to eachcooling unit 904A and 904B for receiving the water from a LAMEE 911 anda recovery coil 912 of each cooling unit 904A and 904B. The water can betransported from one or more tanks to the cold water supply 940.

After the water has provided liquid cooling to the heat load, theincreased temperature water can be transported back to the cooling units904A and 904B through the hot water return 942. The hot water return 942can be fluidly connected to the recovery coil 912 of each of the coolingunits 904A and 904B via water lines 943A and 943B, respectively.

For simplicity, a dotted line box 936 is designated for labelingpurposes only around the LAMEE 911 and recovery coil 912 of each unit904 as described above under FIGS. 3 and 4. FIG. 9 shows the outletlines 941A, 941B and the inlet lines 943A, 943B connected to the box936.

Because the pre-cooler fluid circuit is separate from the process watercircuit in the example of FIG. 9, the conditioning system 900 caninclude a PC cold water main 988 and a PC hot water return 990, both forthe pre-cooler fluid circuit. Each pre-cooler 960 of the cooling units904A and 904B can be fluidly connected to the PC cold water main 988 viawater line 992A and 992B such that reduced-temperature cooling fluid canflow from the PC cold water main 988 and into the pre-cooler 960 of eachcooling unit 904A, 904B. Such reduced-temperature cooling fluid for thepre-coolers 960 can be produced by the auxiliary cooling unit 952 whichcan be configured similar to the auxiliary cooling unit 652 of FIG. 6.The reduced temperature cooling fluid can exit the auxiliary coolingunit 952 and be directed to the PC cold water main 988 via a water line994.

After circulating through the pre-coolers 960 of the cooling units 904Aand 904B, the cooling fluid in the pre-cooler fluid circuit can be at anincreased temperature. Such increased temperature fluid can flow fromeach pre-cooler 960 to the PC hot water return 990 via water lines 996Aand 996B. The increased-temperature fluid can be housed in the PC hotwater return 990 and then can transported back through the auxiliarycooling 952 (via a water line 998) to be cooled again using the LAMEE962 and recover coil 964. The reduced-temperature fluid can exit theauxiliary cooling unit 952 and can be housed in the PC cold water main988. The reduced-temperature fluid can then be circulated back throughthe pre-cooler 960 of each cooling unit 904A and 904B.

For simplicity, the fluid circuits of the LAMEE 962 and recovery coil964 are not shown in FIG. 9 for the auxiliary cooling unit 952. Ratherthe water lines 994 and 998 are shown as being connected to adotted-line box designated as 963 for labeling purposes only. In anexample, the LAMEE 962 and the recovery coil 964, and each of theircorresponding fluid circuits, can be configured similarly to the LAMEE662 and recovery coil 664 of FIG. 6.

In the example of FIG. 9, the conditioning system 900 can include twocooling units 904 and one auxiliary unit 952. It is recognized that moreor less cooling units 904 and more or less auxiliary units 952 can beincluded in the conditioning systems described herein. Multipleauxiliary units 952 can be connected in parallel and can be connected tomultiple process cooling units 904 through the PC cold water main 988and the PC hot water return 990. The process cooling units 904 can alsobe connected in parallel as described above. This design can improveoverall resiliency and redundancy of the system 900. For example, if anyof the auxiliary units 952 fail, the process cooling units 904 canremain functioning at reduced flow rates to account for the failedauxiliary unit.

FIG. 10 illustrates an example conditioning system 1000 that can beconfigured similar to the conditioning system 900 of FIG. 9 and caninclude two or more process cooling units 1004 and one or more auxiliarycooling units 1052. However, in contrast to the conditioning system 900,the auxiliary cooling unit 1052 can function as both an auxiliarycooling unit and a process cooling unit, as described below. Eachprocess cooling unit 1004A and 1004B can include a pre-cooler 1060, aLAMEE 1011 and a recovery or dry coil 1012. The auxiliary cooling unit1052 can include a LAMEE 1062 and recovery coil 1064. Dotted line boxes1036 and 1063 are included in FIG. 10 for simplicity as described abovein reference to FIG. 9.

As described above in reference to the other example conditioningsystems described above, the auxiliary cooling unit 1052 can providecooling to the pre-cooler 1060 by reducing a temperature of a coolingfluid that circulates through the pre-cooler 1060. The pre-cooler 1060can be operational within the process cooling units 1004 during anenhanced operating mode. During the normal and economizer modes, thepre-cooler 1060 can be bypassed or turned off. As such, the auxiliarycooling unit 1052 may not be needed at all times that the processcooling units 1004 are operating for providing the cooling fluid to thepre-cooler 1060. In an example, as shown in FIG. 10, the conditioningsystem 1000 can be configured such that the auxiliary cooling unit 1052can provide process cooling (to the heat load) when it is not needed forproviding reduced-temperature cooling fluid to the pre-cooler 1060.

In the conditioning system 1000, the auxiliary cooling unit 1052 can beswitched from being part of an external cooling circuit for thepre-cooler 1060 to operating as a process cooling unit to providecooling to the heat load. The conditioning system 1000 can include thesame water lines and fluid circuits as the conditioning system 900, withthe difference being that the conditioning system 1000 can includeadditional lines and bypass valves to allow for switching of theauxiliary cooling unit 1052 between operating as a fluid cooler for thepre-coolers 1060 and operating as a process cooling unit for producingreduced-temperature water for delivery to the cold water supply 1040.First, the water lines 1092A and 1092B can each be fluidly connected tobypass valves 1089A and 1089B which can be used to control thedistribution of the cooling fluid from a PC cold water main 1088. Whenthe auxiliary cooling unit 1052 is operating as a fluid cooler for eachpre-cooler 1060, the water can be delivered to each pre-cooler 1060 viawater lines 1091A and 1091B. When the auxiliary cooling unit 1052 isoperating as a process cooling unit to deliver cold water to the heatload, the water from PC cold water main 1088 can be delivered to thecold water supply 1040 via water lines 1092A and 1092B, which can befluidly connected to the water lines 1093A and 1093B. The water can flowfrom the PC cold water main 1088 to the cold water supply 1040 when thevalves 1089A and 1089B are positioned to direct the water through lines1093A and 1093B, rather than through the lines 1091A and 1091B.

Second, the water line 1098 between the PC hot water supply 1090 and theauxiliary cooling unit 1052 can be in connection with a bypass valve1095 that can allow increased-temperature water from the hot waterreturn 1042 to be delivered to the auxiliary cooling unit 1052 via aline 1097 when the auxiliary cooling unit 1052 is operating as a processcooling unit. When the auxiliary cooling unit 1052 is operating as afluid cooler for each pre-cooler 1060 of the process cooling units 1004,the bypass valve 1095 can be configured to close the line 1097 and thusdeliver water from the PC hot water return 1090 to the recovery coil1064 via the water line 1098, which can be connected to the water line1099 into the auxiliary cooling unit 1052. When the auxiliary coolingunit 1052 is operating as a process cooling unit, the bypass valve 1095can be configured to open the line 1097 from the hot water return 1042to the recovery coil 1064 and close the water line 1098 from the PC hotwater return 1090. Thus the water from the hot water return 1042 canenter the auxiliary cooling unit 1052 through the line 1099.

The conditioning system 1000 can include a system controller, similar tothe system controller 148A of FIG. 1A described above, which can controloperation of the conditioning system 1000 between the multiple operatingmodes for the process cooling units 1004A and 1004B. The systemcontroller can also control switching the auxiliary cooling unit 1052between operation as a fluid cooler or as a process cooling unit,depending in part on the operating mode of the process cooling units1004A and 1004B and the quantity of the heat load.

In the conditioning systems shown in FIGS. 1-10, the cooling system orprocess cooling units can be configured such that the evaporative coolercan produce a reduced-temperature fluid, such as water, for providingliquid or air cooling to a heat load. The reduced-temperature fluid fromthe evaporative cooler can be as an alternative to or in addition toreduced-temperature fluid from the recovery coil of the cooling systemor process cooling unit.

FIG. 11 illustrates an example conditioning system 1100 for providingcooling to a heat load 1102. The conditioning system 1100 can include apre-cooler 1160, an evaporative cooler 1110, recovery coil 1112 and afan (or array) 1114, all of which can be arranged inside a scavenger airplenum 1104 (in a similar manner to the components in the scavenger airplenum 104A of FIG. 1A) and thus the plenum 1104 can also be referred toherein as a cooling unit or system 1104. As shown in FIG. 11, thecooling system 1104 can be configured to provide liquid cooling to theheat load 1102 using a scavenger air stream and a reduced-temperaturecooling fluid from the recovery coil 1112. In an example, thereduced-temperature cooling fluid can be water.

In an example, the reduced-temperature water exiting the recovery coil1112 at an outlet 1113 can be transported to a tank 1122 via a waterline 1130. The water can be transported from the tank 1122 to the heatload 1102 (or to a cold water supply) via a water line 1126 and a pump1124. In another example, a tank 1122 can be excluded from the system1000 since the evaporative cooler 1110 is not included in the coolingcircuit that provides cold water for liquid cooling to the heat load1102. The circuit for the evaporative cooler 1110 can be a closed,pressurized hydraulic circuit and does not require an atmosphericpressure tank, as compared to at least some of the systems describedabove. After providing liquid cooling, the increased-temperature watercan be returned to an inlet 1127 of the recovery coil 1112 via a line1128 and the water can be recirculated back through the recovery coil1112.

In contrast to the other conditioning systems shown in FIGS. 1-10, inthe example shown in FIG. 11, a cooling fluid from the evaporativecooler 1110 is not collected for use in providing liquid cooling to theheat load 1102. Rather, in the conditioning system 1100, all of the coldwater for liquid cooling essentially comes directly from the recoverycoil 1112 in all operating modes. The evaporative cooler 1110 canoperate adiabatically and condition the scavenger air such that thescavenger air exiting the evaporative cooler 1110 can cool theincreased-temperature water passing through the recovery coil 1112.Through this adiabatic process, a temperature of the scavenger air at anoutlet of the evaporative cooler 1110 can be less than a temperature ofthe scavenger air at an inlet of the evaporative cooler.

The evaporative cooler 1110 can include an evaporative fluid, which, insome cases, can be recirculated back through the evaporative cooler1110. However, in contrast to the examples described above (which caninclude a LAMEE, for example), the evaporative fluid in the evaporativecooler 1110 is not collected for use in cooling the heat load 1102. Assuch, FIG. 11 does not include a water line from the evaporative cooler1110 to the tank 1122 or a water line from the recovery coil outlet 1113to the evaporative cooler 1110.

In an example, the evaporative cooler 1110 can use media that can besaturated with water. One or more media pads can be configured withinthe plenum 1104 in a generally vertical orientation such that a top ofthe pad can be sprayed with water and the water can drip down the pad tomaintain saturation of the pad. The media pads can be configured to havea large surface area and, in some examples, can be corrugated. As thescavenger air passes through the media pads, the water can beevaporated, thus cooling the air. Any excess water that drips from thepads can be collected and recirculated to the top of the pad. The mediapads can include known materials used in evaporative cooling, such as,for example, cellulose, fiberglass, and paper.

An evaporative media system for the evaporative cooler 1110 can beefficient, low maintenance and have a high cooling capacity. On theother hand, such a system can have low air and water flow limits,limited lifespan of the media (for example, 3-5 years) and water carryover into the scavenger air stream exiting the evaporative cooler 1110.Moreover, the system can have higher water consumption compared to otherevaporative cooler designs.

In an example, the evaporative cooler 1110 can use a water sprayer toinject water into the scavenger air stream. The evaporative cooler 1110can include a plurality of orifices, which can be arranged in an array,to distribute water into the scavenger air. The water can be pressurizedfor sufficient interjection of the water from the nozzle and into theair stream. A water sprayer can be low cost and efficient, but in somecases can require high maintenance and high quality water, such asreverse osmosis water. Depending on the design of the sprayer, it can bebeneficial to have 6 to 8 feet of open space downstream of the sprayer.

In an example, the pre-cooler 1160 can be configured for operatingsimilar to the pre-cooler 160A of FIG. 1A. Water from the tank 1122 canbe delivered to the pre-cooler 1160 using a pump 1172 and a water line1174. However, instead of the increased-temperature water exiting thepre-cooler 1160 being directed into the evaporative cooler 1110, thewater from the pre-cooler 1160 can be delivered through a line 1179 tothe inlet 1127 of the recovery coil 1112 (or to a junction with thewater line 1128) for circulation through the recovery coil 1112.

As shown in FIG. 11, the pre-cooler 1160 can have a coupled coolingfluid circuit such that the cooling fluid circulating through thepre-cooler 1160 can be the water from the tank 1122 and the heated waterexiting the pre-cooler 1160 can be recirculated back through therecovery coil 1112 with the heated water from the heat load 1102 in thewater line 1128. In other examples, the conditioning system 1100 can beconfigured such that the pre-cooler 1160 can have a partially decoupledcooling circuit (see, for example, FIGS. 3 and 4) or a wholly or fullydecoupled cooling circuit (see, for example, FIGS. 5-6 and 9-10).

The conditioning system 1100 can operate in multiple operating modes,including an economizer mode, an adiabatic mode and an enhancedadiabatic mode, which includes the addition of the pre-cooler 1060 tothe adiabatic mode. The selection of the mode can depend in part on theoutdoor air conditions as described above in reference to the otherconditioning systems. Although not shown in FIG. 11, the system 1100 caninclude a system controller that can operate similar to the systemcontrollers 148A and 148B of FIGS. 1A and 1B, respectively.

It is recognized that the conditioning system 1100 can includeadditional components or features not specifically shown in FIG. 11 butdescribed above in reference to other example conditioning systems, suchas, for example, bypass dampers or a LLHX for using the water to cool acoolant that receives heat rejected from the enclosed space or one ormore devices.

The design of the scavenger plenum 1104 of FIG. 11, in which theevaporative cooler 1110 does not provide direct liquid cooling to theheat load 1102, can also be used for the air cooling design shown inFIG. 2. In an example, the scavenger plenum 204 of the conditioningsystem 200 of FIG. 2 can be replaced with the scavenger plenum 1104 asshown in FIG. 11. In such an example, the recovery coil alone, ratherthan the evaporative cooler and recovery coil in combination, can supplythe reduced-temperature water used to provide air cooling to a processair stream through flowing through a LAHX. The design of the scavengerplenum 1104 of FIG. 11 can be used in a conditioning system havingmultiple process cooling units. For example, one or more of the multiplecooling units 404 shown in FIG. 4 can be substituted with the scavengerplenum 1104 of FIG. 11.

FIG. 12 is a flow chart depicting an example method 1200 of operating aconditioning system in accordance with the present application. Themethod 1200 can include in 1202 selectively directing scavenger airthrough a pre-cooler arranged in a scavenger air plenum to condition thescavenger air using a cooling fluid in the pre-cooler. The pre-coolercan selectively be used depending on the conditions of the outdoor air,which can determine an operating mode of the conditioning system. Themethod 1200 can include in 1204 selectively directing scavenger airthrough an evaporative cooler arranged in the scavenger air plenumdownstream of the pre-cooler. The evaporative cooler can selectively beused depending on the conditions of the outdoor air and the determinedoperating mode of the conditioning system. The method 1200 can includein 1206 directing scavenger air through a recovery coil arranged in thescavenger air plenum downstream of the evaporative cooler to produce areduced-temperature cooling fluid. The cooling fluid can circulatethrough the recovery coil and the conditioned scavenger air can be usedto cool the cooling fluid.

The method 1200 can include in 1208 providing liquid cooling or aircooling to a heat load using the reduced-temperature cooling fluid fromthe recovery coil. In an example, the reduced-temperature cooling fluidcan be delivered to the heat load as a process cooling fluid to provideliquid cooling. In an example, some or all of the reduced-temperaturecooling fluid exiting the recovery coil can pass through the evaporativecooler prior to being delivered to the heat load. The heat load can befrom an enclosed space that contains one or more heat generatingcomponents or the heat load can be from one or more devices orcomponents open to the atmosphere. In an example, thereduced-temperature cooling fluid can cool a secondary coolant in aliquid to liquid heat exchanger and the secondary coolant can receiveheat rejected from the enclosed space or one or more devices. In anexample, providing cooling to the heat load in 1208 can include movinghot process air from the enclosed space through a process air plenum tocool the process air through air cooling.

After providing cooling to the heat load, the process cooling fluid canbe at an increased temperature. The method 1200 can include in 1210recirculating the increased-temperature cooling fluid from the heat loadback to the recovery coil.

In an example, the evaporative cooler in 1204 can be configured toprovide liquid or air cooling in combination with thereduced-temperature cooling fluid from the recovery coil. Theevaporative fluid from the evaporative cooler can be collected for usein providing liquid or air cooling in 1208. In an example, a coolingfluid circuit of the evaporative cooler can be in fluid communicationwith a cooling fluid circuit of the recovery coil and the reducedtemperature cooling fluid from the recovery coil can flow through theevaporative cooler for further cooling, prior to being provided to theheat load. In an example, the evaporative cooler in 1204 can selectivelyoperate in an adiabatic mode in which an evaporative fluid in theevaporative cooler can be recirculated back through the evaporativecooler in a closed circuit and thus separate from the cooling fluidcircuit in the recovery coil.

In an example, the cooling fluid in the pre-cooler in 1202 can becoupled with the cooling fluid circuit in one or both of the evaporativecooler and recovery coil. In an example, the cooling fluid in thepre-cooler in 1202 can be coupled with the process cooling fluid circuitthat provides cooling to the heat load. In an example, the cooling fluidin the pre-cooler 1202 can be separate from the process cooling fluidcircuit and can use an external fluid cooler for cooling the coolingfluid in the pre-cooler 1202.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples.” Such examples can include elements in addition tothose shown or described. However, the present inventors alsocontemplate examples in which only those elements shown or described areprovided. Moreover, the present inventors also contemplate examplesusing any combination or permutation of those elements shown ordescribed (or one or more aspects thereof), either with respect to aparticular example (or one or more aspects thereof), or with respect toother examples (or one or more aspects thereof) shown or describedherein.

All publications, patents, and patent documents referred to in thisdocument are incorporated by reference herein in their entirety, asthough individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In this document, the terms “including” and “inwhich” are used as the plain-English equivalents of the respective terms“comprising” and “wherein.” Also, in the following claims, the terms“including” and “comprising” are open-ended, that is, a system, device,article, or process that includes elements in addition to those listedafter such a term in a claim are still deemed to fall within the scopeof that claim. Moreover, in the following claims, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects.

Method examples described herein can be machine or computer-implementedat least in part. Some examples can include a computer-readable mediumor machine-readable medium encoded with instructions operable toconfigure an electronic device to perform methods as described in theabove examples. An implementation of such methods can include code, suchas microcode, assembly language code, a higher-level language code, orthe like. Such code can include computer readable instructions forperforming various methods. The code may form portions of computerprogram products. Further, the code can be tangibly stored on one ormore volatile or non-volatile tangible computer-readable media, such asduring execution or at other times. Examples of these tangiblecomputer-readable media can include, but are not limited to, hard disks,removable magnetic disks, removable optical disks (e.g., compact disksand digital video disks), magnetic cassettes, memory cards or sticks,random access memories (RAMs), read only memories (ROMs), and the like.

Examples, as described herein, may include, or may operate on, logic ora number of components, modules, or mechanisms. Modules may be hardware,software, or firmware communicatively coupled to one or more processorsin order to carry out the operations described herein. Modules mayhardware modules, and as such modules may be considered tangibleentities capable of performing specified operations and may beconfigured or arranged in a certain manner. In an example, circuits maybe arranged (e.g., internally or with respect to external entities suchas other circuits) in a specified manner as a module. In an example, thewhole or part of one or more computer systems (e.g., a standalone,client or server computer system) or one or more hardware processors maybe configured by firmware or software (e.g., instructions, anapplication portion, or an application) as a module that operates toperform specified operations. In an example, the software may reside ona machine-readable medium. In an example, the software, when executed bythe underlying hardware of the module, causes the hardware to performthe specified operations.

Accordingly, the term hardware module is understood to encompass atangible entity, be that an entity that is physically constructed,specifically configured (e.g., hardwired), or temporarily (e.g.,transitorily) configured (e.g., programmed) to operate in a specifiedmanner or to perform part or all of any operation described herein.Considering examples in which modules are temporarily configured, eachof the modules need not be instantiated at any one moment in time. Forexample, where the modules comprise a general-purpose hardware processorconfigured using software; the general-purpose hardware processor may beconfigured as respective different modules at different times. Softwaremay accordingly configure a hardware processor, for example, toconstitute a particular module at one instance of time and to constitutea different module at a different instance of time. Modules may also besoftware or firmware modules, which operate to perform the methodologiesdescribed herein.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. Also, in the above DetailedDescription, various features may be grouped together to streamline thedisclosure. This should not be interpreted as intending that anunclaimed disclosed feature is essential to any claim. Rather, inventivesubject matter may lie in less than all features of a particulardisclosed embodiment. Thus, the following claims are hereby incorporatedinto the Detailed Description, with each claim standing on its own as aseparate embodiment, and it is contemplated that such embodiments can becombined with each other in various combinations or permutations. Thescope of the invention should be determined with reference to theappended claims, along with the full scope of equivalents to which suchclaims are entitled.

The present application provides for the following exemplary embodimentsor examples, the numbering of which is not to be construed asdesignating levels of importance:

Example 1 provides a conditioning system for providing cooling to a heatload, the conditioning system comprising: a scavenger plenum having anair inlet and outlet, the scavenger plenum configured to directscavenger air in an air flow path from the air inlet to the air outlet;an evaporative cooler arranged inside the scavenger plenum in the airflow path and having a first cooling fluid circuit configured tocirculate a first cooling fluid through the evaporative cooler, theevaporative cooler configured to selectively evaporate a portion of thefirst cooling fluid; a first cooling component arranged inside thescavenger plenum between the air inlet and the evaporative cooler, thefirst cooling component configured to selectively condition thescavenger air flowing through the first cooling component; a secondcooling component arranged inside the scavenger plenum between theevaporative cooler and the air outlet and having a second cooling fluidcircuit configured to circulate a second cooling fluid through thesecond cooling component, the second cooling component configured toreduce a temperature of the second cooling fluid using scavenger air;and a process cooling fluid circuit connected to at least one of thefirst cooling fluid circuit and the second cooling fluid circuit, theprocess cooling fluid circuit configured to provide a process coolingfluid to cool the heat load.

Example 2 provides the system of Example 1 and optionally wherein thefirst cooling fluid circuit and the second cooling fluid circuit arefluidly connected, and the first and second cooling fluids are the same.

Example 3 provides the system of Examples 1 and/or 2 and optionally alsowherein the first cooling fluid and the second cooling fluid provide atleast one of liquid cooling or air cooling to the heat load.

Example 4 provides the system of any of Examples 1-3 and optionallywherein the second cooling fluid exiting the second cooling componentselectively flows through the evaporative cooler.

Example 5 provides the system of any of Examples 1-4 and optionallywherein the evaporative cooler is a liquid-to-air membrane energyexchanger (LAMEE), and the first cooling fluid is separated from the airflow path by a membrane, the LAMEE configured to condition the scavengerair and evaporatively cool the first cooling fluid.

Example 6 provides the system of any of Examples 1-4 and optionallyfurther comprising a cooling tower, the cooling tower comprising theevaporative cooler.

Example 7 provides the system of Example 1 and optionally wherein thefirst cooling fluid circuit is separate from the second cooling fluidcircuit, and wherein the second cooling fluid is the process coolingfluid.

Example 8 provides the system of Example 7 and optionally wherein theevaporative cooler includes at least one of an evaporative media or awater sprayer.

Example 9 provides the system of Examples 7 and/or 8 and optionallywherein a remaining portion of the first cooling fluid exiting an outletof the evaporative cooler is recirculated back through the evaporativecooler.

Example 10 provides the system of any of Examples 1-9 and optionallyfurther comprising one or more bypass dampers configured to permitscavenger air to enter or exit the air flow path at one or morelocations between the air inlet and outlet.

Example 11 provides the system of Example 10 and optionally wherein theone or more bypass dampers include a first set of bypass dampersconfigured to direct scavenger air into the air flow path at a locationbetween the first cooling component and the evaporative cooler.

Example 12 provides the system of Examples 10 and/or 11 and optionallywherein the one or more bypass dampers include a second set of bypassdampers configured to direct scavenger air into the air flow path at alocation between the evaporative cooler and the second coolingcomponent.

Example 13 provides the system of any of Examples 1-12 and optionallywherein the evaporative cooler cools the scavenger air such that atemperature of the scavenger air at an outlet of the evaporative cooleris less than a temperature of the scavenger air at an inlet of theevaporative cooler.

Example 14 provides the system of any of Examples 1-12 and optionallywherein the evaporative cooler cools the first cooling fluid such that atemperature of the first cooling fluid at an outlet of the evaporativecooler is less than a temperature of the first cooling fluid at an inletof the evaporative cooler.

Example 15 provides the system of Example 14 and optionally wherein thereduced-temperature first cooling fluid is transported from theevaporative cooler to the process cooling fluid circuit.

Example 16 provides the system of any of Examples 1-13 and optionallywherein the evaporative cooler operates in an adiabatic mode, and thefirst cooling fluid circuit is a closed circuit within the evaporativecooler.

Example 17 provides the system of any of Examples 1-16 and optionallywherein the heat load is from an enclosed space with one or moreheat-generating components.

Example 18 provides the system of Example 17 and optionally furthercomprising: a process plenum configured to direct process air from theenclosed space in an air flow path from a process air inlet to a processair outlet; and a liquid-to-air heat exchanger (LAHX) arranged insidethe process plenum, wherein the LAHX is part of the process coolingfluid circuit and configured to direct the process cooling fluid throughthe LAHX to provide air cooling to the process air flow path, whereinthe process air exiting the process plenum at the process air outlet isreturned to the enclosed space as cool supply air.

Example 19 provides the system of Example 17 and optionally wherein theprocess cooling fluid is delivered to the enclosed space to provideliquid cooling to at least one of process air in the enclosed space orone or more components in the enclosed space.

Example 20 provides the system of any of Examples 17-19 and optionallywherein the enclosed space is a data center.

Example 21 provides the system of any of Examples 1-20 and optionallywherein the first cooling component is a liquid-to-air heat exchanger(LAHX) having a third cooling fluid circuit and configured toselectively circulate a third cooling fluid to condition the scavengerair.

Example 22 provides the system of Example 21 and optionally wherein thethird cooling fluid circuit is fluidly connected to the process coolingcircuit.

Example 23 provides the system of any of Example 21 and optionallywherein the third cooling fluid circuit is fluidly connected to thefirst and second cooling fluid circuits.

Example 24 provides the system of any of Example 21 and optionallywherein the third cooling fluid circuit is separate from the processcooling circuit and the first and second cooling fluid circuits.

Example 25 provides the system of any of Example 24 and optionallywherein the third cooling fluid circuit comprises a fluid coolerconfigured to reduce a temperature of the third cooling fluid exitingthe first cooling component.

Example 26 provides the system of any of Example 25 and optionallywherein the fluid cooler includes a liquid-to-air membrane energyexchanger (LAMEE) arranged inside an auxiliary scavenger air plenum anda recovery coil arranged inside the auxiliary scavenger air plenumdownstream of the LAMEE, and wherein the third cooling fluid flowsthrough at least one of the LAMEE and the recovery coil to reduce atemperature of the third cooling fluid.

Example 27 provides the system of any of Examples 1-16 and optionallywherein the heat load is from one or more devices.

Example 28 provides the system of Example 27 and optionally wherein theone or more devices are contained within an enclosed space.

Example 29 provides the system of Examples 27 and/or 28 and optionallywherein the one or more devices are open to the atmosphere and anexterior of the one or more devices is exposed to outdoor air.

Example 30 provides a method of providing cooling to a heat load, themethod comprising: selectively directing scavenger air through apre-cooling unit arranged in a scavenger air plenum, the scavenger airentering the plenum at an air inlet and exiting the plenum at an airoutlet, and the pre-cooling unit configured to condition the scavengerair entering the plenum; selectively directing the scavenger air exitingthe pre-cooling unit through an evaporative cooler arranged in theplenum, the evaporative cooler having a first cooling fluid circuit andconfigured to selectively evaporate a first cooling fluid in the firstcooling fluid circuit; directing the scavenger air exiting theevaporative cooler through a recovery coil arranged in the plenum, therecovery coil having a second cooling fluid circuit and configured toreduce a temperature of a second cooling fluid in the second coolingfluid circuit using the scavenger air; and providing cooling to the heatload using a process cooling fluid in a process cooling fluid circuit,the process cooling fluid circuit connected to at least one of the firstcooling fluid circuit and the second cooling fluid circuit.

Example 31 provides the method of Example 30 and optionally wherein theprocess cooling fluid includes the first cooling fluid exiting theevaporative cooler.

Example 32 provides the method of Examples 30 and/or 31 and optionallythe method further comprising: transporting at least one of the firstcooling fluid exiting the evaporative cooler and the second coolingfluid exiting the recovery coil to at least one tank to store the atleast one of the first and second cooling fluids prior to using the atleast one of the first and second cooling fluids to provide cooling tothe heat load.

Example 33 provides the method of Example 32 and optionally wherein theprocess cooling fluid is the cooling fluid from the tank.

Example 34 provides the method of any of Examples 30-33 and optionallywherein providing cooling to the heat load using a process cooling fluidincludes: circulating the process cooling fluid through a liquid toliquid heat exchanger (LLHX) to reduce a temperature of a secondarycoolant; and cooling at least one of an enclosed space or one or moredevices using the reduced-temperature secondary coolant.

Example 35 provides the method of any of Examples 30-34 and optionallywherein providing cooling to the heat load using the process coolingfluid includes at least one of air cooling or liquid cooling.

Example 36 provides the method of Example 35 and optionally wherein theheat load is from an enclosed spaced containing one or more heatgenerating components.

Example 37 provides the method of any of Example 36 and optionallywherein the process cooling fluid is delivered to the enclosed space toprovide liquid cooling.

Example 38 provides the method of Example 36 and optionally whereinproviding cooling to the heat load using a process cooling fluidcomprises: delivering the process cooling fluid to a liquid-to-air heatexchanger (LLHX) arranged inside a process air plenum; delivering aprocess air stream from the enclosed space to the LLHX; and reducing atemperature of the process air stream in the LLHX using the processcooling fluid.

Example 39 provides the method of Example 38 and optionally furthercomprising: returning the process air stream to the enclosed space; andreturning the process cooling fluid to at least one of the recovery coiland the evaporative cooler.

Example 40 provides the method of any of Examples 30-34 and optionallywherein providing cooling to the heat load includes delivering theprocess cooling fluid to one or more devices that are open to theatmosphere, and wherein an exterior of the one or more devices isexposed to outdoor air.

Example 41 provides the method of any of Examples 30-40 and optionallywherein selectively delivering scavenger air through a pre-cooling unitincludes using a bypass damper between the pre-cooling unit and theevaporative cooler to bypass the pre-cooling unit depending on outdoorair conditions.

Example 42 provides the method of any of Examples 30-41 and optionallywherein selectively delivering scavenger air through an evaporativecooler includes using a bypass damper between the evaporative cooler andthe recovery coil to bypass the pre-cooling unit and the evaporativecooler depending on outdoor air conditions.

Example 43 provides the method of any of Examples 30-42 and optionallywherein selectively directing the scavenger air exiting the pre-coolingunit through an evaporative cooler comprises: operating the evaporativecooler adiabatically to condition the scavenger air stream in theevaporative cooler; and recirculating the first cooling fluid throughthe evaporative cooler such that the first cooling fluid circuit is aclosed circuit in the evaporative cooler.

Example 44 provides the method of Example 43 and optionally wherein afirst tank stores the process cooling fluid prior to providing coolingto the heat load, and wherein a second tank is part of the closedcircuit in the evaporative cooler.

Example 45 provides the method of any of Examples 30-44 and optionallywherein selectively directing the scavenger air exiting the pre-coolingunit through an evaporative cooler includes reducing a temperature ofthe scavenger air in the evaporative cooler such that a temperature ofthe scavenger air at an outlet of the evaporative cooler is less than atemperature of the scavenger air at an inlet of the evaporative cooler.

Example 46 provides the method of any of Examples 30-42 and optionallywherein the first and second cooling fluid circuits are fluidlyconnected and the first and second cooling fluids are the same fluid.

Example 47 provides the method of Example 46 and optionally wherein theprocess cooling fluid includes the first and second cooling fluids andthe method further comprises: recirculating the first and second coolingfluids through the recovery coil and the evaporative cooler.

Example 48 provides the method of any of Examples 30-47 and optionallywherein selectively directing scavenger air through a pre-cooling unitarranged in a scavenger air plenum includes circulating a third coolingfluid through the pre-cooling unit to condition the scavenger air.

Example 49 provides the method of Example 48 and optionally wherein thethird cooling fluid is in a third cooling fluid circuit connected to theprocess cooling fluid circuit.

Example 50 provides the method of Examples 48 and/or 49 and optionallywherein the third cooling fluid is in a third cooling fluid circuitconnected to the first and second cooling fluid circuits.

Example 51 provides the method of Example 48 and optionally wherein thethird cooling fluid is in a third cooling fluid circuit separate fromthe process cooling circuit and the first and second cooling fluidcircuits, and the method further comprises: directing the third coolingfluid exiting the pre-cooling unit through an auxiliary cooling unitconfigured to reduce a temperature of the third cooling fluid; andrecirculating the reduced-temperature third cooling fluid through thepre-cooling unit during operation of the pre-cooling unit.

Example 52 provides a conditioning system for providing cooling to aheat load, the conditioning system comprising: a plurality of processcooling units, each process cooling unit configured to produce areduced-temperature cooling fluid and comprising: a scavenger plenumhaving an air inlet and outlet, the scavenger plenum configured todirect scavenger air in an air flow path from the air inlet to the airoutlet; an evaporative cooler arranged inside the scavenger plenum inthe air flow path and having a first cooling fluid circuit configured tocirculate a first cooling fluid through the evaporative cooler, theevaporative cooler configured to selectively evaporate a portion of thefirst cooling fluid; a first cooling component arranged inside thescavenger plenum between the air inlet and the evaporative cooler, thefirst cooling component configured to selectively condition thescavenger air flowing through the first cooling component; and a secondcooling component arranged inside the scavenger plenum between theevaporative cooler and the air outlet and having a second cooling fluidcircuit configured to circulate a second cooling fluid through thesecond cooling component, the second cooling component configured toreduce a temperature of the second cooling fluid; and a process coolingfluid supply circuit connected to at least one of the first and secondcooling fluid circuits of each of the plurality of cooling units andconfigured to supply a process cooling fluid to the heat load to causeheat rejected by the heat load to be received by the process coolingfluid, the process cooling fluid comprising at least one of the firstand second cooling fluids; and a process cooling fluid return circuitconfigured to receive the process cooling fluid after the processcooling fluid receives heat rejected by the heat load and to return theprocess cooling fluid back to each of the plurality of process coolingunits for recirculation through at least one of the second coolingcomponent and the evaporative cooler of each of the plurality of processcooling units.

Example 53 provides the system of Example 52 and optionally wherein eachprocess cooling unit further comprises: a tank configured to receive andtemporarily store at least one of the first and second cooling fluidsprior to supplying the process cooling fluid to the heat load.

Example 54 provides the system of Example 53 and optionally wherein thetank is located inside the scavenger plenum.

Example 55 provides the system of Example 53 and optionally wherein thetank is located outside of the scavenger plenum.

Example 56 provides the system of any of Examples 52-55 and optionallywherein the evaporative cooler of each process cooling unit is aliquid-to-air membrane energy exchanger (LAMEE) and the first coolingfluid is separated from the scavenger air by a membrane.

Example 57 provides the system of any of Examples 52-56 and optionallywherein the evaporative cooler of each process cooling unit isconfigured to selectively operate adiabatically and the first coolingfluid circuit includes a selectively closed circuit within theevaporative cooler.

Example 58 provides the system of any of Examples 52-57 and optionallywherein the first cooling fluid circuit of each process cooling unit isconnected to the second cooling fluid circuit.

Example 59 provides the system of Example 58 and optionally wherein thereduced-temperature second cooling fluid selectively flows through theevaporative cooler prior to exiting the scavenger plenum.

Example 60 provides the system of any of Examples 52-58 and optionallywherein the first cooling component of each process cooling unit is aliquid-to-air heat exchanger (LAHX) having a third cooling fluid circuitand configured to selectively circulate a third cooling fluid tocondition the scavenger air.

Example 61 provides the system of Example 60 and optionally wherein theprocess cooling fluid supply circuit provides a portion of the processcooling fluid to the first cooling component for use as the thirdcooling fluid.

Example 62 provides the system of Examples 60 and/or 61 and optionallywherein the third cooling fluid exits the first cooling component at anincreased-temperature and is transported to the process cooling fluidreturn circuit.

Example 63 provides the system of Example 60 and optionally furthercomprising an auxiliary cooling unit configured to reduce a temperatureof the third cooling fluid exiting the first cooling component of one ormore of the process cooling units in the plurality of process coolingunits.

Example 64 provides the system of Example 63 and optionally wherein theauxiliary cooling unit includes a liquid-to-air membrane energyexchanger (LAMEE) arranged inside an auxiliary scavenger air plenum anda recovery coil arranged downstream of the LAMEE in the auxiliaryscavenger air plenum, and wherein the third cooling fluid flows throughat least one of the LAMEE and the recovery coil to reduce a temperatureof the third cooling fluid.

Example 65 provides the system of Examples 63 and/or 64 and optionallywherein the auxiliary cooling unit selectively operates to provideprocess cooling fluid to the process cooling fluid supply circuit whenthe plurality of process cooling units are operating in a mode in whichthe first cooling component of each process cooling unit is bypassed.

Example 66 provides the system of any of Examples 52-65 and optionallywherein the heat load is from an enclosed space with one or moreheat-generating components.

Example 67 provides the system of Example 66 and optionally wherein theenclosed space is a data center.

Example 68 provides a conditioning system for providing cooling to aheat load, the conditioning system comprising: a process cooling unitcomprising: a scavenger air plenum having an air inlet and outlet, theplenum configured to direct scavenger air in an air flow path from theair inlet to the air outlet; an evaporative cooler arranged inside theplenum in the air flow path and having a first cooling fluid circuitconfigured to selectively circulate a first cooling fluid through theevaporative cooler, the evaporative cooler configured to selectivelyevaporate a portion of the first cooling fluid; a pre-cooler arrangedinside the plenum upstream of the evaporative cooler, the pre-coolerhaving a second cooling fluid circuit configured to selectivelycirculate a second cooling fluid through the pre-cooler to selectivelycondition the scavenger air, prior to selectively passing the scavengerair through the evaporative cooler; and a recovery coil arranged insidethe plenum downstream of the evaporative cooler, the recovery coilhaving a third cooling fluid circuit configured to circulate a thirdcooling fluid through the recovery coil, the recovery coil configured toreduce a temperature of the third cooling fluid; a process cooling fluidcircuit connected to at least one of the first cooling fluid circuit andthe third cooling fluid circuit, the process cooling fluid circuitconfigured to supply at least one of the first cooling fluid and thethird cooling fluid to the heat load to cause heat rejected by the heatload to be received by the at least one of the first and third coolingfluids; and an auxiliary cooling unit configured to cool the secondcooling fluid exiting the pre-cooler, wherein the auxiliary cooling unitis part of the second cooling fluid circuit and separate from the firstand third cooling fluid circuits.

Example 69 provides the system of Example 68 and optionally wherein theevaporative cooler is a LAMEE, and the process cooling fluid circuitsupplies the first and third cooling fluids to the heat load.

Example 70 provides the system of Examples 68 and/or 69 and optionallywherein the evaporate cooler selectively operates adiabatically and thefirst cooling fluid circuit is a closed circuit, and wherein the processcooling fluid circuit supplies the third cooling fluid to the heat load.

Example 71 provides the system of any of Examples 68-70 and optionallywherein the auxiliary cooling unit comprises a LAMEE arranged inside anauxiliary scavenger air plenum and a recovery coil arranged downstreamof the LAMEE in the auxiliary scavenger air plenum, and wherein thesecond cooling fluid flows through at least one of the LAMEE and therecovery coil to reduce a temperature of the second cooling fluid.

Example 72 provides the system of any of Examples 68-71 and optionallywherein the auxiliary cooling unit is configured to selectively operatewhen the pre-cooler is used to condition the scavenger air, and theauxiliary unit is not in operation when the pre-cooler is bypassed.

Example 73 provides the system of any of Examples 68-72 and optionallywherein the auxiliary cooling unit is configured to selectively providean auxiliary cooling fluid to the heat load when the pre-cooler isbypassed.

Example 74 provides a method of providing cooling to a heat load, themethod comprising: selectively directing scavenger air through apre-cooler arranged inside a scavenger air plenum, the scavenger airentering the plenum at an air inlet and exiting the plenum at an airoutlet, the pre-cooler having a first cooling fluid circuit configuredto selectively circulate a first cooling fluid through the pre-cooler toselectively condition the scavenger air; selectively directing the firstcooling fluid exiting the pre-cooler through an auxiliary cooling unitto decrease a temperature of the first cooling fluid; selectivelydirecting the scavenger air through an evaporative cooler arrangedinside the scavenger air plenum downstream of the pre-cooler, theevaporative cooler having an evaporative cooler fluid circuit configuredto circulate an evaporative cooler fluid through the evaporative cooler,and the evaporative cooler configured to selectively evaporate a portionof the evaporative cooler fluid; directing the scavenger air through arecovery coil arranged inside the scavenger air plenum downstream of theevaporative cooler, the recovery coil having a second cooling fluidcircuit configured to circulate a second cooling fluid, and the recoverycoil configured to reduce a temperature of the second cooling fluidusing scavenger air; and supplying a process cooling fluid in a processcooling fluid circuit to the heat load, the process cooling fluidreceiving heat rejected by the heat load, wherein the process coolingfluid circuit is connected to the second cooling fluid circuit and theprocess cooling fluid comprises the second cooling fluid, and whereinthe first cooling fluid circuit is separate from the second coolingfluid circuit.

Example 75 provides the method of Example 74 and optionally furthercomprising: delivering the reduced-temperature first cooling fluid backto the pre-cooler after the first cooling fluid circulates through theauxiliary cooling unit.

Example 76 provides the method of Examples 74 and/or 75 and optionallywherein the process cooling fluid is at an increased-temperature afterreceiving heat rejected by the heat load, and the method furthercomprise: delivering the increased-temperature process cooling fluid tothe recovery coil.

Example 77 provides the method of any of Examples 74-76 and optionallywherein selectively directing the first cooling fluid exiting thepre-cooler through an auxiliary cooling unit comprises: directing thefirst cooling fluid through a recovery coil arranged in an auxiliaryscavenger air plenum to reduce a temperature of the first cooling fluid;and selectively directing the reduced-temperature first cooling fluidexiting the recovery coil through a LAMEE arranged in the auxiliaryscavenger air plenum upstream of the recovery coil.

Example 78 provides the method of any of Examples 74-77 and optionallywherein a portion of the evaporative cooler fluid is collected and usedas the process cooling fluid in the process cooling fluid circuit.

Example 79 provides the method of any of Examples 74-78 and optionallywherein the evaporative cooler is a LAMEE comprising an evaporativefluid flow path separate from an air flow path, and wherein the flowpaths are separated by a membrane.

Example 80 provides a system or method of any one or any combination ofExamples 1-79, which can be optionally configured such that all steps orelements recited are available to use or select from.

Various aspects of the disclosure have been described. These and otheraspects are within the scope of the following claims.

1-51. (canceled)
 52. A conditioning system for providing cooling to aheat load, the conditioning system comprising: a plurality of processcooling units, each process cooling unit configured to produce areduced-temperature cooling fluid and comprising: a scavenger plenumhaving an air inlet and outlet, the scavenger plenum configured todirect scavenger air in an air flow path from the air inlet to the airoutlet; an evaporative cooler arranged inside the scavenger plenum inthe air flow path and having a first cooling fluid circuit configured tocirculate a first cooling fluid through the evaporative cooler, theevaporative cooler configured to selectively evaporate a portion of thefirst cooling fluid; a first cooling component arranged inside thescavenger plenum between the air inlet and the evaporative cooler, thefirst cooling component configured to selectively condition thescavenger air flowing through the first cooling component; and a secondcooling component arranged inside the scavenger plenum between theevaporative cooler and the air outlet and having a second cooling fluidcircuit configured to circulate a second cooling fluid through thesecond cooling component, the second cooling component configured toreduce a temperature of the second cooling fluid; and a process coolingfluid supply circuit connected to at least one of the first and secondcooling fluid circuits of each of the plurality of cooling units andconfigured to supply a process cooling fluid to the heat load to causeheat rejected by the heat load to be received by the process coolingfluid, the process cooling fluid comprising at least one of the firstand second cooling fluids; and a process cooling fluid return circuitconfigured to receive the process cooling fluid after the processcooling fluid receives heat rejected by the heat load and to return theprocess cooling fluid back to each of the plurality of process coolingunits for recirculation through at least one of the second coolingcomponent and the evaporative cooler of each of the plurality of processcooling units.
 53. The conditioning system of claim 52 wherein eachprocess cooling unit further comprises: a tank configured to receive andtemporarily store at least one of the first and second cooling fluidsprior to supplying the process cooling fluid to the heat load.
 54. Thecooling system of claim 53 wherein the tank is located inside thescavenger plenum.
 55. The cooling system of claim 53 wherein the tank islocated outside of the scavenger plenum.
 56. The cooling system of claim52 wherein the evaporative cooler of each process cooling unit is aliquid-to-air membrane energy exchanger (LAMEE) and the first coolingfluid is separated from the scavenger air by a membrane.
 57. The coolingsystem of claim 52 wherein the evaporative cooler of each processcooling unit is configured to selectively operate adiabatically and thefirst cooling fluid circuit includes a selectively closed circuit withinthe evaporative cooler.
 58. The cooling system of claim 52 wherein thefirst cooling fluid circuit of each process cooling unit is connected tothe second cooling fluid circuit.
 59. The cooling system of claim 58wherein the reduced-temperature second cooling fluid selectively flowsthrough the evaporative cooler prior to exiting the scavenger plenum.60. The cooling system of claim 52 wherein the first cooling componentof each process cooling unit is a liquid-to-air heat exchanger (LAHX)having a third cooling fluid circuit and configured to selectivelycirculate a third cooling fluid to condition the scavenger air.
 61. Theconditioning system of claim 60 wherein the process cooling fluid supplycircuit provides a portion of the process cooling fluid to the firstcooling component for use as the third cooling fluid.
 62. Theconditioning system of claim 61 wherein the third cooling fluid exitsthe first cooling component at an increased-temperature and istransported to the process cooling fluid return circuit.
 63. Theconditioning system of claim 60 further comprising an auxiliary coolingunit configured to reduce a temperature of the third cooling fluidexiting the first cooling component of one or more of the processcooling units in the plurality of process cooling units.
 64. Theconditioning system of claim 63 wherein the auxiliary cooling unitincludes a liquid-to-air membrane energy exchanger (LAMEE) arrangedinside an auxiliary scavenger air plenum and a recovery coil arrangeddownstream of the LAMEE in the auxiliary scavenger air plenum, andwherein the third cooling fluid flows through at least one of the LAMEEand the recovery coil to reduce a temperature of the third coolingfluid.
 65. The conditioning system of claim 63 wherein the auxiliarycooling unit selectively operates to provide process cooling fluid tothe process cooling fluid supply circuit when the plurality of processcooling units are operating in a mode in which the first coolingcomponent of each process cooling unit is bypassed.
 66. The conditioningsystem of claim 52 wherein the heat load is from an enclosed space withone or more heat-generating components.
 67. The conditioning system ofclaim 66 wherein the enclosed space is a data center. 68-73. (canceled)74. A method of providing cooling to a heat load, the method comprising:selectively directing scavenger air through a pre-cooler arranged insidea scavenger air plenum, the scavenger air entering the plenum at an airinlet and exiting the plenum at an air outlet, the pre-cooler having afirst cooling fluid circuit configured to selectively circulate a firstcooling fluid through the pre-cooler to selectively condition thescavenger air; selectively directing the first cooling fluid exiting thepre-cooler through an auxiliary cooling unit to decrease a temperatureof the first cooling fluid; selectively directing the scavenger airthrough an evaporative cooler arranged inside the scavenger air plenumdownstream of the pre-cooler, the evaporative cooler having anevaporative cooler fluid circuit configured to circulate an evaporativecooler fluid through the evaporative cooler, and the evaporative coolerconfigured to selectively evaporate a portion of the evaporative coolerfluid; directing the scavenger air through a recovery coil arrangedinside the scavenger air plenum downstream of the evaporative cooler,the recovery coil having a second cooling fluid circuit configured tocirculate a second cooling fluid, and the recovery coil configured toreduce a temperature of the second cooling fluid using scavenger air;and supplying a process cooling fluid in a process cooling fluid circuitto the heat load, the process cooling fluid receiving heat rejected bythe heat load, wherein the process cooling fluid circuit is connected tothe second cooling fluid circuit and the process cooling fluid comprisesthe second cooling fluid, and wherein the first cooling fluid circuit isseparate from the second cooling fluid circuit.
 75. The method of claim74 further comprising: delivering the reduced-temperature first coolingfluid back to the pre-cooler after the first cooling fluid circulatesthrough the auxiliary cooling unit.
 76. The method of claim 74 whereinthe process cooling fluid is at an increased-temperature after receivingheat rejected by the heat load, and the method further comprise:delivering the increased-temperature process cooling fluid to therecovery coil.
 77. The method of claim 74 wherein selectively directingthe first cooling fluid exiting the pre-cooler through an auxiliarycooling unit comprises: directing the first cooling fluid through arecovery coil arranged in an auxiliary scavenger air plenum to reduce atemperature of the first cooling fluid; and selectively directing thereduced-temperature first cooling fluid exiting the recovery coilthrough a LAMEE arranged in the auxiliary scavenger air plenum upstreamof the recovery coil.
 78. The method of claim 74 wherein a portion ofthe evaporative cooler fluid is collected and used as the processcooling fluid in the process cooling fluid circuit.
 79. The method ofclaim 78 wherein the evaporative cooler is a LAMEE comprising anevaporative fluid flow path separate from an air flow path, and whereinthe flow paths are separated by a membrane.